Influence Of Solution Treatment Research Articles

The influence of solution treatment on the phase evolution and tensile properties of binary Ti-Mo alloys

The influence of solution treatment on the phase evolution and tensile properties of Ti-Mo alloys was investigated to assess their potential use in biomedical applications. Phase formation and microstructural evolution were studied using X-ray diffraction (XRD), optical microscopy (OM), scanning electron microscopy (SEM), and electron backscatter diffraction (EBSD). The mechanical properties were characterized by means of tensile tests and bending strength. XRD analysis showed that solution treatment increased the volume fraction of ß phase and supressed the α" phase. The microstructures of the as-cast alloys consisted of ß equiaxed grains with sub-grain structures of different sizes, while the solution treated alloys comprised ß equiaxed grains only except for Ti-10.02Mo, which comprised needle-like a" structures. EBSD showed an increase in the volume fraction of the ω and α" phases in all the alloys after solution treatment. The elastic modulus and UTS of all the alloy significantly decreased after solution treatment, except for Ti-15.05Mo, whereas the elongation significantly increased. The fracture surfaces of all the alloys after solution treatment indicated more ductile behaviour than brittle.

Unraveling the effects of solution treatment on the microstructure and corrosion behavior of HT-HAZ in duplex stainless steel welded joints

Abstract In this work, the influence of solution treatment on the corrosion behavior and microstructure of HT-HAZ was studied. The results show that the balanced two-phase ratio is discovered after solution treatment. After solution treatment at 960°C, a small amount of chromium nitride remains at the two-phase interface and in the ferrite. With the solution treatment temperature increasing to 1120°C, chromium nitride can be fully dissolved. The chemical elements of the two-phase are redistributed during the solution treatment process, which results in changes in PREN. After solution treatment, the proportion of recrystallized grains increases whereas that of sub-structured grains decreases, indicating the reduction of residual stresses and deformations. The percentage of CSL boundaries increases as the solution treatment temperature rises. Compared with HT-HAZ without solution treatment, the improved corrosion resistance after solution treatment is ascribed to the balanced two-phase ratio, less chromium nitride precipitates, smaller residual deformations, and more CSL boundaries. However, the pitting resistance after solution treatment at 960°C is still relatively poor on account of the residual chromium nitride. The pitting nucleation sites are closely associated with the chromium nitride precipitates and PREN of two-phase.

Revealing the influence of solution and pre-deformation treatment on the corrosion resistance of Y-modified AZ91 magnesium alloy for lithium-ion battery shell

The usage of Mg–Al–Zn alloys for lithium-ion battery shell is able to achieve further lightweight of electric vehicles, and their corrosion resistance would highly determine the service life. In this work, therefore, a Y-modified AZ91 magnesium alloy (AZ91-0.5Y) was first prepared by conventional casting and following hot extrusion, and the influence of solution treatment (ST) and subsequent pre-deformation (SP) treatments on its electrochemical corrosion and stress corrosion cracking (SCC) resistance in 1 mol/L LiPF6 electrolyte were then investigated. The results indicated that the presence of large lamellar or rod-like β-Mg17Al12 phase in as-extruded AZ91-0.5Y alloy would lead to serious micro-galvanic corrosion and SCC. After solution treatment, the β-Mg17Al12 phase almost completely dissolved into Mg matrix, weakening the micro-galvanic corrosion and anodic dissolution (AD) and hydrogen embrittlement (HE) effect. Further, the subsequent pre-deformation treatment could introduce dislocation, more precipitation of Al2Y phase, massive twins and optimized texture, leading to the improved corrosion resistance and mechanical strength as well as the formation of well-integrated protective corrosion product film MgF2 with low porosity. As a result, the corrosion and SCC resistance of as-extruded, ST and SP specimens is ordered from low to high.

Microstructural Evolution and Mechanical Behavior of TA15 Titanium Alloy Fabricated by Selective Laser Melting: Influence of Solution Treatment and Aging

In this study, TA15 titanium alloys were successfully prepared using selective laser melting (SLM). The results show that the microstructure of each TA15 specimen is composed of a large number of acicular α’ martensite crystals accompanied by a lot of dislocations and twin structures in the martensite due to non-equilibrium heating and cooling via SLM. After solution treatment and aging treatment, the martensite structure is successfully transformed into a typical duplex structure and an equiaxial structure. When there is an increase in the solution temperature, the size of the equiaxed primary α phase and the elongation of the specimen gradually increases, while the thickness of the layered secondary α phase and the tensile strength of the specimen decreases accordingly. After solution treatment at 1000 °C, the specimens show the best comprehensive mechanical properties, i.e., a high-temperature tensile strength of 715 MPa and a corresponding elongation of 24.5%. Subsequently, an appropriate solution–aging treatment is proposed to improve the high-temperature mechanical properties of SLMed TA15 titanium alloys in aerospace.

Influences of solution treatments on the microstructure and mechanical properties of TiCx-Cu (x = 0.5, 0.6, 0.7) cermets prepared by infiltration method

In this study, TiCx-Cu (x = 0.5, 0.6, 0.7) cermets were prepared combined with subsequent solution treatment, and the influences of solution treatment on the microstructures and mechanical properties were analyzed. The fracture mechanisms of cermets before and after solution treatment were mainly observed and analyzed. The results show that solution treatment can significantly improve the comprehensive mechanical properties of TiCx-Cu cermets. The fracture toughness KIC of TiC0.5-Cu and TiC0.7-Cu cermets increased by 28% and 11%, respectively. The improvements of the comprehensive properties of TiCx-Cu cermets were benefited by the reduction of the content of hard brittle intermetallic compound Cu4Ti and the refinements of the grain size of Cu.

Influence of Solution Treatment and Artificial Aging onFracture Load of Friction Stir Welded Lap Joints of AA2014-T6

High strength aluminium alloys (2xxx and 7xxx) are widely used for many applications. Particularly, aircraft and automobile industries. The fabrication of this alloy is little bit difficult using traditional welding process. It produces porosity, alloy segregation, partially melted zone etc. In last few decades, these alloys are welded using a solid-state welding process, friction stir welding. However, the strength of the alloy is more than 80% of the base material strength. Although, the FSW joints have lowest hardness in the weld region due to heterogeneous properties in the microstructure. The lowest hardness region is the soft region that is the fracture-originating region during tensile test. Several techniques were used to enhance the lowest hardness region properties such as the aging process, the solution treatment process, cryogenic treatment in joints. In this research, the solution treatment followed by artificial aging on lap shear strength of friction stir lap-welded joints were performed. The heat-treated joints were compared with welded joints. From the experimental results, the heat-treated joints yield higher lap shear strength than the as welded joints. The reason for the higher lap shear strength was reprecipitation of precipitates in the welded joints during an artificial aging process. However, the aluminium matrix retains fine precipitates by the solution treatment process (under rapid cooling).

Influence of solution treatment on microstructures and mechanical properties of a naturally-aged Al–27Zn–1.5Mg–1.2Cu–0.08Zr aluminum alloy

Solution treatment and natural aging have been carried out to enhance the mechanical properties of a high-Zn aluminum alloy (Al–27Zn–1.5Mg–1.2Cu–0.08Zr) produced by melt spinning and extrusion. The studies show that the as-extruded alloy contains lots of Zn particles, Zn-rich η-MgZn2 particles at grain boundaries and oxidation films at ribbon interfaces. The Zn particles and Zn-rich η-phases can be fully dissolved at 370 °C and 450 °C respectively. However, when solution temperature is higher than 400 °C, the brittle oxide films are difficult to accommodate the plastic strains caused by thermal contraction during quenching, which may result in over-heating and quench cracking. The optimized solution temperature for the high-Zn aluminum alloy is 400 °C. The solution-treated alloys reveal a strong naturally age hardening. Both η′-phase and GP-zones are the main hardening phases for the naturally peak-aged alloy solution-treated at 400 °C, whereas GP-zones exist as the main hardening phase for the alloys solution-treated at 350 °C. Naturally peak-aged alloy solution-treated at 400 °C shows the highest strength and elongation among all of the experimental alloys. Its superior strength is mainly due to its higher-density of dispersed nano-sized precipitates and higher η′-phase percentage.

Heat Treatment of Low Cost Beta Titanium Alloy Produced by Investment Casting

Beta (β) Ti-alloys are promising class of Ti-alloys for high performance structural applications, thanks to their high strength to weight ratios and outstanding corrosion resistance. In the current work, Ti-4.5Fe-7Cr low cost beta Ti-alloy was produced by investment casting. DSC test was carried out to determine the transformation temperatures. The influence of solution treatment and aging temperatures on microstructure and mechanical properties were studied. Six heat treatment cycles were carried out, two solution treatment cycles in β- and α+β-range at 900 °C and 750 °C, respectively, and four precipitation hardening cycles, i.e. α+β-aging at 450 °C and 650 °C after solution treating at both 900 °C and 750 °C. Microstructure examination, XRD analysis and compression test had been conducted to investigate the influence of the different heat treatment regimes on the proposed alloy. Solution treatment at 900 °C results in coarser β-grain size than at 750 °C; hence lower strength. Strengthening by α-phase precipitation and grain refinement was achieved during aging. Aging at 650 °C results in higher strength than at 450 °C although coarser grain size, this is attributed to stronger effect of precipitation hardening of α-phase at 650 °C as a result of its higher amount than at 450 °C. The designed alloy shows high strength and excellent malleability, i.e. the alloy reveals superior plastic deformability, where specimens did not reveal any fracture; and the compression tests were interrupted at a compressive strain of 33%; therefore, this alloy may find applications as a healthcare, automotive or aerospace material.

The Influence of Solution Treatments on the Microstructure, Phase Transformation Behavior, and Superelastic Characteristics of Nitinol Synthesized by Plasma Arc Deposition

The aim of this work is to study the effect of solution treatment time on the Ti2Ni second phase morphology, phase transformations, mechanical properties and superelastic behavior of plasma arc deposited (PAD) nitinols. The results demonstrate that the Ti2Ni second phases are significantly affected by the solution treatment time. The Ti2Ni second phase is dissolved into the TiNi matrix phase gradually, and its size and volume fraction also gradually decreases with increasing solution treatment time. Additionally, the solution treatment time exhibits a visible influence on the phase transformation, mechanical properties and superelasticity of the PAD nitinol, but the degree of influence depends on the size, volume fraction and distribution of the Ti2Ni second phase. With increasing solution treatment time, the phase transformation temperatures gradually increase, and the phase transformation peaks decrease in width and become sharp with a single transformation. Besides, the compressive strength first increases and then decreases, while the plasticity increases with solution treatment time increases from 0 to 8 h. Moreover, the superelastic stability of the PAD nitinol is improves as the solution treatment time increases from 0 to 6 h and then decreases. This phenomenon is closely related to the critical stress for dislocation slip, which depends on the change in the Ti2Ni second phase.

Influence of Solution Treatment on Microstructure and Electrical Conductivity of Wrought Al-15Si Alloy

In the present work, the microstructures and electrical conductivity of Al-15Si alloy in casting, extruding and solution treatment conditions were investigated. The results indicate that the extruded Al-15Si alloy has higher electrical conductivity. It has been revealed that the morphology of Si, iron element and grain boundary impact on electrical conductivity of the Al-Si alloy. With the revolution of the microstructure, these factors which lead to the changing electrical conductivity of the alloy are discussed in detail.

Influence of solution treatment on microstructural evolution and mechanical properties of a new titanium alloy

Influence of solution treatment on microstructural evolution and mechanical properties of a new titanium alloy

Influence of solution treatment on microstructure, corrosion resistance, and oxidation behavior of cast G-NiCr28W alloy

G-NiCr28W is a nickel-based cast alloy. Its microstructure consists of nickel-rich matrix phase and chromium-rich eutectic carbides. The solution treatment process can provide homogenous microstructure and desired mechanical/thermal properties for G-NiCr28W alloy. However, the solution treatment process affects the corrosion resistance of the alloy and it causes metal loss due to the occurrence of oxidation at atmospheric conditions. Therefore, determining the changes in the properties of the G-NiCr28W is important. For this purpose, G-NiCr28W specimens were solution treated at 1,040 ˚C, 1,100 ˚C and 1,160 ˚C for 1 h and 8 h, respectively. The microstructures of the solution-treated samples were characterized by optical microscopy, scanning electron microscopy, energy dispersive spectroscopy and X-ray diffraction analysis. Moreover, hardness, corrosion resistance and oxidation behaviors of the solution-treated samples were examined. The solution treatment process applied at 1,160 ˚C led to the formation of Fe2W2C blocky carbides, and hardness of the sample increased with the existence of blocky carbides, while corrosion resistance decreased. Furthermore, excessive metal loss occurred depending on oxidation due to the high process temperature at 1,160 ˚C.

Effect of Solution Treatment on Microstructure and Selected Mechanical Properties of an (α+β) Titanium Alloy

The influence of solution treatment on the microstructure and mechanical properties of an (α+β) high temperature titanium alloy (Ti-6.5Al-2Sn-4Zr-5Mo-1W-0.2Si) are investigated by optical microscope (OM), scanning electron microscopy (SEM), electron probe microanalysis (EPMA) and tensile tests at room and elevated temperatures. The results shows that, Ti-6.5Al-2Sn-4Zr-5Mo-1W-0.2Si alloy after simple solution treatment has good combinations of plasticity and tensile strength both at room and high temperature. With the solution temperature increasing, the volume fraction of primary α phase (αp) decreases gradually, while the volume fractions of β matrix (βt) and secondary α phase (αs) increase. Room and high temperature tensile properties are insensitive with microstructure after solution treatment. With the solution temperature increasing, the content of αp phase decreases while the content and size of βt increase, which would cause the strength increase and plasticity decrease at RT and 650°C.

Influence of solution treatment on microstructure and stress rupture properties of K439 nickel-base superalloy

The isochronal solution treatment (4h) in the 1080-1190°C range with air cooling are performed to investigate the effects of solution temperature on the microstructure and stress rupture properties of K439 alloy. The detailed as-cast and solution treated microstructures were analyzed through optical microscopy (OM), scanning electron microscopy (SEM) and differential scanning calorimeter (DSC). The experimental results show that the as-cast alloy exhibited a typical dendritic structure with five phases of γ, γ´, γ/γ´, η and MC. After solution heat treated at 1080°C, although all of the γ´ particles in the dendritic cores were dissolved, there were still some of these precipitates in the interdendritic regions beside η phase. With the solution temperature increasing to 1150°C, all of the γ´ and η solutioned and a uniform microstructure was observed. Furthermore, increasing the temperature to 1210°C, a small amount of incipient melting occurred in the alloy. The stress rupture life of K439 alloy at 760°C/530MPa increased with the rising of solution temperature and reached to the top value under the solution temperature of 1150°C. The optimum solution treatment considered to be 1150 C/4 h followed by air cooling.

Implications of solution treatment on cavitation erosion and corrosion resistances and synergism of austenitic stainless steel

This paper looks into the influences of solution treatment on the cavitation erosion and corrosion resistances of a CrMnNi austenitic stainless steel. Cavitation erosion pit formation is mainly associated with twin boundaries, slip lines and martensite traces (ε and α′). These pits subsequently grow both across slip lines and martensite traces and along twin boundaries, eventually coalescing to form bigger ones. Conducting solution treatment at an excessively high temperature will result in significant grain growth that compromises strength, reduces corrosion resistance and facilitates martensite formation, thereby causing a deterioration in both cavitation erosion and corrosion resistances.

Effect of solution treatment on microstructure and properties of duplex stainless steel

The influence of solution treatment on microstructure and properties of 2205 duplex stainless steel (DSS) was studied. The microstructure, precipitates and corrosion resisting property were observed and analyzed by means of optical microscopy (OM), scanning electron microscopy (SEM) and electrochemical methods. The results showed that a large number of brittle σ-phase precipitates, which deteriorate the plasticity and corrosion resistance of the material, were easy to produce in the duplex stainless steel under the low temperature. The precipitation of σ-phase can be decreased and the plasticity and corrosion resistance can be improved by increasing solution temperature. In addition, the ferrite content increases with the increase of solution temperature, while less affected by cooling rate.

Evolution of microstructure and tensile properties during solution treatment of nickel-based UNS N10276 alloy

Influence of solution treatment (ST) on microstructure evolution and mechanical behavior of nickel-based UNS N10276 alloy were investigated by a variety of techniques such as optical metallography, scanning electron microscopy, transmission electron microscopy and tensile testing. The average grain size remained almost unaffected by hold time at 1050°C, resulting from the pinning effect of secondary phase on the grain boundary. A sharp increase in grain size and grain growth rate was observed with increasing solutionizing temperature up to 1150°C irrespective of hold time, which was mainly related to the complete dissolution of precipitated particles as well as to the enhanced diffusion of solute atoms. The rate of grain growth reduced with extending solutionizing time and decreasing temperature. Flow curve parameters based on Ludwigson equation for the alloy after heat treatment were determined. The dissolution of secondary phase particles, combined with the grain growth, increased the work hardening exponent (n) and dramatically improved the tensile ductilities (TD), but reduced the tensile strengths (TS) to large extent. Both TD and n monotonically increased with increasing solutionizing temperature and prolonging hold time as the alloy was solutionized beyond 1100°C, while the TS and strain hardening rate (SHR) showed a reverse varying trend to that of TD and n. As the heat treatment was performed at 1050°C, tensile properties were not monotonically changing with hold time, which is associated with the increase in amount of precipitates and with the Ostwald ripening of precipitated particles. On the basis of Hall–Petch relation and experimental data, the mathematical relationships between tensile properties and grain size of the alloy solutionized at temperatures higher than 1150°C, were obtained by linear regression analysis. The Hall–Petch strengthening coefficient for yield strength of the UNS N10276 alloy was estimated to be 18.35MPamm1/2.

Improving bioactivity of inert bioceramics by a novel Mg-incorporated solution treatment

Zirconia/alumina ceramics possess outstanding mechanical properties for dental and orthopedic applications, but due to their poor surface bioactivities they exhibit a weak bone-bonding ability. This work proposes an effective 30-min solution treatment which could successfully induce formation of bone-like apatite on the surface of 3Y-TZP and a ternary composite composed of yttria-stabilized zirconia, ceria-stabilized zirconia, and alumina (35 vol% 3Y-TZP+35 vol% 12Ce-TZP+30 vol% Al2O3) after 3 weeks immersion in simulated body fluid (SBF). XRD was used for phase identification in the ceramic materials. The influence of solution treatment on the surface chemistry and its role on apatite formation were investigated via SEM, EDS and XPS. In vitro apatite-forming ability for the solution-treated and untreated samples of the composite and individual substrates of 3Y-TZP, 12Ce-TZP, and Al2O3 was evaluated by immersion in SBF. Apatite crystals were formed only on 3Y-TZP and composite substrates, implying that it is mainly the 3Y-TZP constituent that contributes to the bioactivity of the composite. Further, it was found from the XPS analysis that the zirconia material with higher phase stability (12Ce-TZP) produced less ZrOH functional groups on its surface after solution treatment which accounts for its weaker bioactivity compared to 3Y-TZP.

THE INFLUENCE OF SOLUTION TREATMENT ON THE STRUCTURE AND MECHANICAL AND TRIBOLOGICAL PROPERTIES OF MAGNESIUM ALLOY WE54

The paper presents the influence of solution treatment on the mechanical and tribological properties of the WE54 magnesium alloy. The investigated alloy was solution treated at a temperature of 545oC for 8 hours and cooled in ice water (0oC), in room temperature water (20oC), and in hot water (95oC). Depending on the applied solution treatment parameters, a diversified decrease in hardness and Young's modulus was obtained. The lowest values of hardness H and modulus E were obtained when cooling in ice water. Abrasive wear of alloy WE54 was tested using a ball-on-disc tribometer (with a ZrO2 ball). The tests have shown more than a threefold reduction in the volumetric wear and a twofold reduction in the linear wear, as well as favourable changes of the friction coefficient (a 20% decrease) as compared to the material in the as-received condition.

Effect of Solution Treatment on Microstructure Evolution and Mechanical Behavior of Cu-20Ni-20Mn Alloy

The influence of solution treatment on microstructure evolution and mechanical behavior of Cu-20Ni-20Mn alloy was investigated by optical microscopy (OM), X-ray diffraction (XRD) and hardness test. The results revealed that both solution temperature and holding time had effect on the grain growth behavior. The grain growth activation energy was determined by grain size of Cu-20Ni-20Mn alloy for different heat treatment temperatures and periods. With increasing temperature of solution treatment, the second phase is gradually dissolved into the Cu-rich matrix, and the lattice parameter of the matrix solution treated at 1173K for 0.5 h was about 3.668 Å. The hardness of the solution-treated alloy was lower than that of hot forging, and the hardness value decreased with the increase of solution temperature, which may be attributed to grain size. The hardening ability, corresponding to the Hall-Petch relationship, decreased linearly with D-1/2.