Cold Rolling Process Research Articles

Research on the microstructure and properties of metastable β type Ti-8V4Mo3Cr3Zr3Al alloy with high strength and toughness

In this paper, a new type of Ti-8V-4Mo-3Cr-3Zr-3Al metastable β-type titanium alloy is designed based on alloy design parameters such as valence electron concentration (VEC), Bo, and Md, and combines them with the empirical criterion of molybdenum equivalent fractionation. Optimize the microstructure of the alloy through processes such as cold rolling, annealing, and aging treatment to obtain good mechanical properties. The microstructure of cold rolling and post rolling heat treatment was observed and analyzed using optical microscopy (OM), scanning electron microscopy (SEM), X-ray diffraction (XRD), and transmission electron microscopy (TEM), and the tensile properties of the alloy were tested. The characteristics of the alloy in terms of microstructure and properties were summarized and analyzed. The results show that the cold formability of the alloy after solid solution treatment is good, with a cold rolling reduction of over 85 %, and a large number of deformation twins generated during the cold rolling process. The yield strength after annealing and recrystallization is up to 1160 MPa, and elongation is 18.9 %. The final performance of the aged alloy is 1510 MPa for yield strength and 5 % for elongation.

Unveiling the effect of strain path-dependent microstructural evolution on the electrochemical behavior of cold-rolled [FeNi]69Cr15Mn10Nb6 high-entropy alloy

In the present work, [FeNi]69Cr15Mn10Nb6 high-entropy alloys (HEAs) were subjected to a heavy cold-rolling process at ambient temperature through two distinct routes, namely unidirectional cold-rolling (UCR) and multistep cross cold-rolling (MSCCR). This was done to investigate the effect of strain path-dependent microstructural evolution on the electrochemical behavior of the alloys in a 0.5 M H2SO4 solution. The as-homogenized specimen displayed a two-phase microstructure with [FeNiNb]-rich dendrites distributed in a nearly homogenous face-centered cubic (FCC) high-entropy alloy matrix. It was found that the [FeNiNb]-rich dendrites elongated, broke down, and elongated along the rolling direction in both processing routes. In the MSCCR-processed specimen, the dendrites exhibited a smaller average size with a more uniform distribution compared to the UCR sample, which was mainly ascribed to the elongation mechanisms in the normal and transverse directions during the MSCCR route. Electrochemical studies demonstrated a decrease in corrosion current density due to high imposed strains in the UCR. Meanwhile, a more positive trend was observed in MSCCR processing. Consequently, achieving uniformly distributed small dendrites and uniform grain refinement through the MSCCR route provided ideal conditions for forming passive layer with superior protection properties.

Study on the uniaxial tensile mechanical behavior and constitutive model of advanced high-strength steels for DP1180 and Q&P1180

With the increasing global demand for green and environmentally friendly materials, advanced high-strength steels (AHSS) produced using by cold rolling process are gaining more attention in the construction industry, such as in cold-formed thin-walled structures. To expand their engineering applications, the study of the mechanical behavior and constitutive models of AHSS is particularly important. This paper focuses on DP1180 and Q&P1180, employing experimental research and theoretical analysis to elucidate the patterns at various characteristic points and establish constitutive models for AHSS. The specific conclusions are as follows: 1) For DP1180 and Q&P1180, the average elongation after fracture is 8.9 % and 16.7 %, respectively, with strength-to-yield ratios ranging from 1.24 to 1.34 and 1.14–1.24, respectively. 2) Due to the insignificant nonlinearity exhibited by DP1180 and Q&P1180 near the nominal buckling strength, the modified nominal yield strength and equivalent ultimate strength was defined and adopted as the boundaries to divide the stress-strain curve into three segments. The mathematical expressions and relevant parameter models for each segment are established. Finally, the three-stage AHSS uniaxial tensile constitutive model was established. Compared to existing models, the proposed model demonstrates higher accuracy.

Ameliorating the microstructure and properties of a Cu[sbnd]Cr alloy by introducing a high-temperature short-time treatment into the thermo-mechanical process

The optimization of process is essential for improving the overall properties of high-strength and high-conductivity Cu alloys. This study introduces a high-temperature short-time treatment (HTSTT, 850 °C/5 min) into the thermo-mechanical process of a CuCr alloy. Following the process of “solid solution - cold rolling - HTSTT - cold rolling - aging”, the tensile strength of the alloy increases from 450 MPa to 508 MPa, with the electrical conductivity increasing from 82.2 %IACS to 86.4 %IACS when compared to the conventional process of “solid solution - cold rolling - aging” under the same total deformation condition. The reasons for the improvement in the comprehensive properties of the alloy after introducing HTSTT are analyzed through microstructural characterization. The results indicate that the HTSTT promotes the occurrence of recrystallization, leading to grain refinement, which results in smaller grain sizes during subsequent processing. Additionally, the introduction of HTSTT changes the main texture of the alloy from 〈100〉//X to 〈111〉//X during the process, which is beneficial to enhancing the alloy's strength and electrical conductivity. More importantly, the HTSTT facilitates the precipitation of solute Cr atoms, leading to the formation of a significant quantity of nanoscale Cr particles, most of which are spherical with an average size of 27 nm. During the subsequent cold rolling process, these Cr particles effectively pin dislocations and promote their proliferation, leading to the precipitation of a large number of smaller Cr particles during the aging process, with an average size of 4.8 nm. These finer Cr particles are crucial for precipitation strengthening. This paper offers valuable insights into the microstructural optimization and performance enhancement of high-strength and high-conductivity Cu alloys.

Severe plastic cold rolling effects in nickel–vanadium alloy: Microstructure, texture evolution and mechanical properties

The microstructural characteristics and morphological attributes of the target material, along with its intrinsic properties, can significantly influence the performance of the resultant film. Currently, commercially available nickel-vanadium targets employed in the industry have not been subjected to investigations aimed at controlling grain size and grain orientation. This study examines the effects of unidirectional rolling at room temperature, combined with substantial deformation, on the alterations in microstructure, texture evolution, and mechanical properties of the NiV7 alloy. The process of severe plastic cold rolling leads to a continuous elongation and refinement of the grains. The changes in microstructure and texture of the cold-rolled sheets were analyzed using electron backscatter diffraction (EBSD) technology. At an 80% reduction, a significant number of sub-grains are observed, which transform into deformed grains as the reduction reaches 95%. With a thickness reduction of 96.6%, the average grain size is approximately 1.10 μm. Further increases in reduction do not lead to significant alterations in the grain structure; instead, the grain orientation progressively becomes more uniform with higher levels of deformation. The combination of substantial deformation and lower rolling rates results in an increased number of high-angle grain boundaries. The alloy displays various textures throughout the rolling process, including S-type, copper-type, brass-type, fiber, and cubic textures. Notably, the prevalence of S-type and fiber textures diminishes as the degree of deformation increases, while the cubic texture becomes increasingly prominent. Upon achieving a reduction of 95%, the cubic texture emerges as the dominant texture. A transmission electron microscope (TEM) was utilized to examine the extensive array of dislocations, dislocation cells, dislocation walls, and shear bands generated during the cold rolling process. At a deformation level of 96.6%, the ultimate tensile strength of the alloy demonstrates a significant enhancement, attributed to mechanisms of dislocation strengthening and grain strengthening, reaching a value of 1231 ± 20 MPa, accompanied by a post-fracture elongation of approximately 2%. The ultimate tensile strength exhibited an increase of 781 ± 20 MPa compared to the sample prior to the rolling process; however, there was a notable reduction in plasticity.

Bond strength empirical-mathematical equation and optimization of Al1050/AISI304 bilayer sheets fabricated by cold roll bonding method

Nowadays, composite sheets have been increasingly developed in various applications due to their better corrosion and wear resistance as well as higher strength and formability. Of these, Al/SS bilayer sheets have been used in the food and automotive industries due to their favorable performance and low cost. In this research, the bonding strength of Al1050/AISI304 bilayer sheets fabricated by cold roll bonding has been investigated experimentally. At first, the design of the experiment was carried out using the surface response method, taking into account the thickness of the layers and the rolling reduction ratio, bilayer sheet using the rolling bonding method. In this research, for the first time, the bonding strength of Al/SS bilayer sheets fabricated by cold rolling bonding method and its optimization have been investigated. The bond strength was extracted using T peeling test. Then, using the linear regression method, a mathematical-experimental relationship was presented to obtain the peeling strength in terms of the thickness of the layers and the reduction ratio. The obtained results were analyzed using statistical methods and the table of coefficients, the table of residuals and the analysis of variance table of the data related to bond strength were presented and the adequacy of the presented model was examined. The results showed that by reducing the reduction ratio in the cold rolling process and also reducing the initial thickness of the sheets, the bond strength of the bilayer sheet has decreased. Then, bond strength optimization was done as a function of input parameters. The results indicated that the bonding strength reached its maximum level at the thickness of the aluminum layer = 2 mm, the thickness of the stainless-steel layer = 1.3 mm and reduction = 75%.

EFFECT OF STRAIN PATH ON MICROSTRUCTURE AND MECHANICAL PROPERTIES IN COLD - ROLLED [FeNi]69Cr15Mn10Nb6 HIGH - ENTROPY ALLOY

[FeNi]69Cr15Mn10Nb6 high - entropy alloys (HEAs) were subjected to heavy cold-rolling process at ambient temperature through two distinct routes, namely unidirectional cold-rolling (UCR) and multistep cross cold-rolling (MSCCR) routes, to investigate the effect of the strain path on the microstructure and mechanical properties of the alloys. In the MSCCR route, the specimen rotated 90° around the normal direction axis between each cycle. The as-homogenized specimen revealed a two-phase microstructure consisting of FeNiNb - rich dendrites distributed in a nearly homogenous face-centered cubic (FCC) HEA matrix. Here, FeNiNb - rich dendrites were elongated,broken down, and stretched along the rolling direction during both processing routes. In the MSCCR - processed specimen, the dendrites exhibited a smaller average size with a more uniform distribution compared to that of the UCR specimen, which could be mainly ascribed to the elongation mechanisms in the normal and transverse directions during the MSCCR route. These microstructural features, introduced through MSCCR, appeared to be most prone to shear band formation and grain refinement. The MSCCR - processed specimen shows a microhardness of 445 HV, a tensile strength of 1245 MPa, and a remarkable elongation of 16 % at ambient temperature, outperforming the UCR-processed specimen with a microhardness of 418 HV, a tensile strength of 1180 MPa, and an elongation of 14 %. The superior mechanical properties of the MSCCR - processed specimen are attributed to its refined microstructure,increased dislocation density, and uniform distribution of FeNiNb - rich dendrites within the microstructure.

Effect of Cold Rolling on the Microstructure and High Temperature Properties of 310S Heat-resistant Steel

Abstract The microstructure and high temperature properties of 310S heat-resistant steel were investigated before and after cold rolling with a deformation rate of 10% by using optical microscopy (OM), scanning electron microscopy (SEM), X-ray diffractometer (XRD) and tensile testing machine.The results showed that the microstructure of 310S heat-resistant steel remains unchanged with no formation of any new phase observed after cold rolling. The hardness is enhanced from 305.4HV prior to cold rolling to 321.6HV post cold rolling, exhibiting an augmentation of 16.2HV. The 310S heat-resistant steel is carried out a cold-rolling process with a deformation of 10% in the room temperature tensile test. The tensile strength exhibits an increase from 776.6MPa to 806.3MPa, with a difference of 29.7MPa.The yield strength has experienced a significant increase, from 554.4MPa to 679.6MPa, representing a substantial increment of 125.2MPa.The elongation decreased by 20.2%, from 61.9% to 41.7%, after cold rolling. The 310S heat-resistant steel with 0% deformation appears superplasticity at 750°C. The elongation rate reaches 113.1%. The 310S heat-resistant steel with 0% deformation appears fracture oxidation at 800°C. In the process of 700°C to 800°C, the tensile strength of 310S heat-resistant steel with 0% deformation is reduced by 101.9MPa, and the tensile strength of 310S heat-resistant steel with 10% deformation is reduced by 90.9MPa.

TRIBOLOGICAL INVESTIGATION OF TUNGSTEN CARBIDE AND HARD CHROME COATINGS ON EN19 FOR COLD ROLLING APPLICATION

In the heavy sheet metal industry, rolls are generally made up of EN19. To enhance the life of the cold rolling mills it can be coated. This paper presents an experimental study to check the effect of alloy coatings such as Hard Chrome and Tungsten carbide on wear resistance and other characteristics of roller base materials EN19 which is used in rolling process of heavy metal industry. In this paper a comparative tribological study of Hard Chrome, Tungsten carbide, EN19 through hardness testing, surface roughness analysis, SEM, and EDS, XRD, sliding wear experiments and statistical study through Design of Experiment has been performed to find out the best material which can increase the life of rolls. From the experiments carried out it has been found that hardchrome has 15.19 times the longevity of the substrate EN19. Tungsten carbide has 19 times the life of EN19 and 1.25 times the life of hardchrome. Tungsten carbide coating gives more hardness and wear resistance than the Hard Chrome and EN19 base material of the roll. Thus, using Tungsten carbide coating on EN19 rolls will improve the life and enhance the longevity of the roll used in cold rolling process in heavy steel industry.

Effect of intermediate annealing temperature and cold rolling deformation on the texture of yttrium bearing oriented silicon steel

The cold rolling and intermediate annealing process, along with the incorporation of rare earth elements, play an important role in the microstructure, texture, and inhibitors of oriented silicon steel. Currently, there is limited research on the impact of rare earth yttrium on texture evolution during the cold rolling and intermediate annealing processes. Therefore, the effects of different cold rolling deformations and intermediate annealing temperatures on the microstructure and texture of Y bearing oriented silicon steel have been studied. The experimental results demonstrate that the average grain size of the intermediate annealed plate progressively decreases with increasing the cold rolling deformation. This is because the high cold rolling deformation brings more additional dislocations and distortions, consequently enhancing the driving force for recrystallization. Observing the microstructure with various cold rolling deformation, the results show that the annealed plate with a 72 % reduction rate exhibited the highest Goss texture percentage of 4.83 %. This is because the cold-rolled sheet with a reduction rate of 72 % exhibits an abundance of Goss oriented substructures. These substructures quickly dominate the {111}<112> deformed matrix during the initial recrystallization, and promote grains nucleation and growth. As the annealing temperature increases, the driving force for the growth of recrystallized grains also increases, leading to a gradual increase in grain size. The plate annealed at 940 °C exhibits the highest percentage (4.83 %) of Goss texture. The addition of rare earth Y can lead to an increase in grain size in the intermediate annealed plate and facilitate the formation of {411}<148> texture. This is advantageous for the abnormal growth of Goss texture. The results demonstrate that a cold rolling deformation rate of 72 % and an intermediate annealing temperature of 940 °C are good for promoting abnormal growth of Goss orientation. The study results on precipitation kinetics suggests that the grain boundary nucleation of AlN and dislocation nucleation of MnS are the most effective way of nucleation. The precipitates in oriented silicon steel without Y are Al2O3 and MnS, while those in the samples with Y are AlN, YS, and YOxSy. The addition of rare earth Y leads to a reduction in both the density and size of precipitates. Moreover, With the increase of annealing temperature, the size of precipitates decreases and the amount of precipitates increases. Additionally, the addition of Y makes the steel more clean, meanwhile, the pinning effect of inclusions on grain boundaries is weakened. Therefore, the grain size of the steel with Y is larger.

Optimization of mechanical, corrosion properties and cytotoxicity of biodegradable Zn-Mn alloys by synergy of high-pressure solidification and cold rolling process

Zinc (Zn) and Zn-based alloys are biodegradable materials, that have recently gained significant research attention due to their moderate degradation rate and good biocompatibility. However, their clinical applications are limited by their inferior mechanical properties. In this study, Zn-0.5Mn, Zn-1.0Mn, and Zn-1.5Mn (wt%) alloys were prepared via high-pressure solidification (HPS) and cold rolling (CR) procedures. Further, the microstructure, mechanical properties, corrosion behavior, and in-vitro cytotoxicity of these Zn-Mn alloys were systematically investigated. The results revealed that their yield strength (σys) and ultimate tensile strength (σUTS) enhanced significantly after synergy of HPS-CR treatment compared to CR alone. Notably, among these alloys, the Zn-1.5Mn alloy exhibited the highest σys and σUTS after HPS-CR, at 296.4±5.4 MPa and 322.6±3.5 MPa, respectively. The primary reason for this phenomenon is attributed to the combination of grain refinement and solid solution strengthening performance. Furthermore, these newly designed biodegradable Zn-Mn alloys exhibited appropriate in-vitro degradation rates and acceptable in vitro cytocompatibility when tested in Hanks' solution.

Study on precipitation in (CoCrFeMnNi)90Al6Ti4 high entropy alloy

(CoCrFeMnNi)90Al6Ti4 high entropy alloy (HEA) was prepared by adding Al and Ti elements into CoCrFeMnNi HEA. The alloy underwent processes including copper mold suction casting, 1473 K homogenization, 30 % cold rolling + 1273 K annealing + 1073 K aging, and water quenching and heating treatment. Microstructure and phase composition of both as-cast and heat-treated (CoCrFeMnNi)90Al6Ti4 HEA were studied using metallographic microscope, scanning electron microscope (SEM), energy dispersive spectrometer (EDS), X-ray diffractometer (XRD), and transmission electron microscope (TEM). The effect of heat treatment processes on the precipitation of second phases in (CoCrFeMnNi)90Al6Ti4 HEA was investigated, and mechanical properties of as-cast and heat-treated (CoCrFeMnNi)90Al6Ti4 HEA were studied via hardness tests. The results show that in as-cast (CoCrFeMnNi)90Al6Ti4 HEA, the second phase precipitated is primarily L21 structured AlTiNi2 phase. After homogenization, cold rolling, annealing, and aging processes, both the quantity and size of the second phase increase, with a small amount of nanoscale L12 phase appearing after aging treatment. With the progression of heat treatment, the hardness of (CoCrFeMnNi)90Al6Ti4 HEA increases, and mechanical properties are improved.

Effect of Annealing after Casting and Cold Rolling on Microstructure and Electrochemical Behavior of High-Entropy Alloy, Cantor

High-entropy alloys (HEAs), a relatively new class of materials, have attracted significant attention in materials science owing to their unique properties and potential applications. High entropy stabilizes the phase of a solid solution over a wide range of chemical compositions, yielding unique properties superior to those of conventional alloys. Therefore, this study analyzed the microstructure and electrochemical behavior of HEAs (Cantor) to evaluate their corrosion resistance, according to their manufacturing process (casting, cold rolling, and annealing). The microstructural morphologies and sizes were analyzed using electron backscatter diffraction. The electrochemical behavior was examined using open circuit potential measurements, electrochemical impedance spectroscopy, potentiodynamic polarization tests, and critical pitting temperature measurements using a potentiostat. The casting process formed a nonuniform microstructure (average grain size = 19 μm). The cold rolling process caused the formation of fine grains (size = 4 μm). A uniform microstructure (grain size &gt; 151 μm) was formed after heat treatment. The corrosion resistance of the HEAs was determined from the passivation layer formed by Cr oxidation. These microstructural differences resulted in variations in the electrochemical behavior. Microstructural and electrochemical analyses are crucial because HEAs have diverse potential applications. Therefore, this study contributes to future improvements in HEA manufacturing processes.

Effect of Intermediate Annealing on Microstructure and Cold Rolling Hardness of AlFeMn Alloy

The microstructure and texture of an AlFeMn alloy were studied under different intermediate annealing processes, and the changes in microhardness during cold rolling were analyzed. After annealing at 420 °C with a slow heating rate, the alloy showed a high number of small dispersed particles and recrystallization textures dominated by R texture, with deformation textures of 23.5%. Annealing at 610 °C with a rapid heating rate resulted in a significant decrease in the number of small-sized particles and an increase in recrystallization texture contents, with CubeND being the majority. The deformation texture contents decreased to 14.9%. The electrical conductivity of the 420 °C annealed sheet was higher than before annealing, whereas the sheet annealed at 610 °C showed a decrease in electrical conductivity after annealing. This indicated that annealing at 610 °C led to a higher degree of recrystallization and the development of Cube/CubeND due to the dissolution of dispersed particles. During the subsequent cold rolling process, the microhardness of both annealed sheets initially increased and then decreased. However, the microhardness of the 420 °C annealed sheet with varying cold rolling reductions consistently remained lower than that of the 610 °C annealed sheet, as was the cold rolling reduction corresponding to the peak microhardness. The results showed that the precipitation at 420 °C facilitated work softening, while the dissolution at 610 °C promoted work hardening.

Investigation and optimization on the formability of aluminum 1050/stainless steel 304L bilayer sheets fabricated by cold roll bonding considering the Box-Behnken method

Composite metal sheets have found extensive applications thanks to their high corrosion and wear resistance, as well as greater strength, stiffness, and formability relative to the base sheets. Stainless steel composite sheets account for over 80% of the metallic composite sheets. Their higher performance and lower costs have increased their applications in the food and automotive industries. This study experimentally addressed the formability of the Al 1050/Stainless Steel 304 L bilayer sheets prepared through the cold rolling process. After designing the experiment using the response surface method, considering the layer thickness and reduction ratio of the rolling process, the bilayer sheets were prepared using the cold roll bonding process. Formability included the forming limit diagram, the magnitude of FLD0, and elongation, which were derived by Nakazima and tensile tests. Then, the formability was optimized as a function of input parameters considering the Box-Behnken method. To this end, a new criterion was presented to compare the formability of the sheets. This criterion can be used to assess the formability of a sheet considering various loading modes. Microstructural observations justified the variations in the formability of the bilayer sheets against the input parameters, i.e., thickness ratio and reduction ratio. The results indicated that the formability of the Al 1050/Stainless Steel 304 L bilayer sheet (i.e., safe forming region) reached its maximum value at tAl=4mm;tSS=0.8mm;andr=45%.

Research on deformation behaviors at different temperatures of lean duplex stainless steel S32101 produced by direct cold rolling process

In this paper, the mechanical properties, work hardening characteristics and deformation mechanism of lean duplex stainless steel (LDSS) S32101 produced by direct cold rolling were studied under different temperature conditions. The yield strength (YS) and tensile strength (TS) of S32101 decreased with the increase of deformation temperature, while the elongation increased first and then decreased. The TS of S32101 at −70 °C was 1052.6 MPa, the elongation remained 57.2%, and the product of strength and elongation (PSE) was as high as 60.2 GPa·%, which was mainly due to the synergistic strengthening of transformation induced plasticity (TRIP) and twinning-induced plasticity (TWIP) effects in austenite at cryogenic temperatures. The efficiency of grain refinement at cryogenic temperature was improved by TRIP effect and deformation twins (DTs), indicating that it had the potential to be applied at low temperature (−70 ∼ −30°C). Moreover, the high density nanotwins and the strong interaction between the dislocation and nanotwin bundles also contributed to strain hardening at low temperatures and thus better comprehensive mechanical properties could be achieved.

Development of the method for determining the plane cross-wall diversity of cold-rolled pipes on the basis of experimental research with different options of feeding and turning

In recent years, cold pipe rolling mills have been used in Ukraine, where it is possible to perform different modes of feeding and turning the pipe. Formulation of the problem. We need a method that makes it possible to plan the cross-wall variation of the pipes. Goal. Development of a method for determining the planned diversity for the design of production technology to ensure the regulated increased quality of pipes according to their geometry. Methodology. Obtaining experimental results on the effect of feeding and turning modes during cold rolling on the cross-wall variation of pipes. Mode 1 – the feed is performed before the forward movement, and the turn before the reverse movement of the cage; mode 2 - the feed is performed before the forward movement, and the turn is performed before the forward and reverse movement of the cage; mode 3 – feeding is performed in the front and back position of the cage, and the turn is in the back position; mode 4 – feeding and rotation are performed before the forward and reverse movement of the cage). The results. Of the tested modes, mode 2 and mode 4 are the most effective (from the point of view of correcting the cross-sectional variation of the pipe blanks. Scientific novelty. First, additional experimental data were obtained on the magnitude of the cross-sectional variation of the pipes during the cold rolling process of the pipes with different modes of feeding and turning in front of the straight and It is shown that the process of cold rolling of pipes with feed in front of the direct and turning before the direct and reverse movement of the cage gives 1.5 times better indicators in terms of tube accuracy compared to feeding in front of the direct movement of the cage and turning before the reverse movement of the cage. Тhe indicators are given by the process with forward and reverse motion of the cage. Practical significance. The obtained results are needed in the development of technologies for the production of pipes with increased requirements for transverse diversity

An investigation to microstructural and texture evolution during the cold rolling of Al0.3CoCrFeNi high entropy alloy

In the present study, Al0.3CoCrFeNi high entropy alloy (HEA) was subjected to thickness reductions through cold rolling process in order to thoroughly investigate the evolution of microstructure and deformation texture. Important aspects of deformed microstructures such as the formation of twinning bundles and shear bands in the specimens were monitored. The evolution of texture during the cold rolling process was measured by X-Ray Diffraction (XRD) and Electron Back Scatter Diffraction (EBSD) technique which revealed the formation of Copper type texture at the initial stages of rolling due to slip deformation mechanism. Originated from twinning and followed by shear banding, the texture was subsequently developed toward predominantly Brass type. Microstructural features and texture evolution behavior of the investigated single phase FCC alloy was attributed to its low SFE level. Visco Plastic Self Consistent (VPSC) technique was coupled in the research to simulate the material behavior and to examine the contribution of slip and twinning systems. Benefiting VPSC justifications, the texture transition from Copper type to Brass type was related to lower CRSS value of slip in comparison to twinning at the small strains which was then grows faster at the later stages of rolling facilitating the onset of twinning and providing the texture transition basement.

Calculation of the CRSS ratios of Ti80 alloy and its application in prediction of texture in Pilger cold rolling

The accurate critical resolved shear stress (CRSS) ratios of different slip systems and deformation history are vital for the texture simulation and controlling for Ti80 alloy pipe during Pilger cold rolling process. This study proposed a comprehensive framework for determining these parameters. A method to calculate the CRSS ratio based on the statistics of activated slip systems was proposed, which could effectively eliminate the error of activated slip systems proportion caused by microtexture. No twinning was observed in the deformation of Ti80 alloy, and the activated slip systems of {0002}<11 2‾ 0>, {101‾ 0}<112‾ 0>, {101‾ 1}<112‾ 0> and {112‾ 2}<112‾ 3> were observed through uniaxial in-situ tensile test combined with EBSD at room temperature. And the CRSS ratio of Ti80 alloy has been calculated approximately as τBasal<a>: τPrism<a>: τPyram<a>: τPyram<a> = 1:0.8:3.5:6. Based on visco-plastic self-consistent (VPSC) model and the calculated CRSS, the texture with shear strain and without shear strain was simulated respectively in the Pilger cold rolling process. Meanwhile, the mechanism of texture formation was analyzed. The texture component was [0001] ‖ TD, and [11-20]‖ AD when the traditional velocity gradient neglecting shear strain was adopted in simulation. However, the shear strain in ZR direction would cause the texture to rotate 30° around the [0001] axis. Compared with that only considering the velocity gradient in the normal strain direction, the rolling texture can be more accurately predicted when considering the history of velocity gradient in all directions.

The Effect of Rolling Reduction on the Microstructure Evolution and Slip Behavior of Ta-10W Alloy during Cold Rolling Process

In this study, we investigated the influence of cold rolling reduction on microstructural evolution and slip behavior in Ta-10W alloy fabricated by vacuum arc melting (VAM). As the reduction increased, both single and multiple slips were observed within some grain interiors. At reductions of 20% and 40%, deformation bands, primarily consisting of γ-fiber components, formed within the grain interiors. The fraction of deformation bands (DBs) increased with higher reduction. Conversely, at 60% reduction, in addition to DBs, experimentally observed shear bands (SBs) with a herringbone pattern were formed. Both DBs and SBs predominantly formed in regions of concentrated strain (areas with high kernel average misorientation (KAM) and geometrically necessary dislocations (GND)). As the reduction increased, the misorientation angle between the matrix and the DBs or SBs gradually increased, while the width of the DBs decreased. To investigate the violation of Schmid’s law in Ta-10W alloy, slip trace and resolved shear stress (RSS) analyses were performed on observed slip lines within deformed grains. Contrary to conventional slips, where slip typically occurs on the plane with the highest RSS, slips in the Ta-10W alloy were confirmed to occur even on planes with lower RSS in certain grains. Hence, this study provides experimental evidence of Schmid’s law violation in Ta-10W alloy.