Effect Of Thermomechanical Treatment Research Articles

Influence of Thermomechanical Treatments and Chemical Composition on the Phase Transformation of Cu-Al-Mn Shape Memory Alloy Thin Sheets

This paper investigates the interrelated effects of thermomechanical treatments and chemical composition on the phase transformation capabilities of thin sheets made from Cu-Al-Mn shape memory alloys. The transformation capacity and transition temperatures were determined using DSC and DMA testing, while composition measurements were performed using SEM/EDX analysis. The results demonstrate that applying hot-rolling treatments to alloys of reduced thickness leads to manganese oxidation and modifications in chemical composition, adversely impacting the phase transformation performance. This effect can be mitigated by the use of cold rolling. Additionally, the presence of phosphorus impurities can create inclusions that bind manganese, preventing it from remaining in the solid solution and further affecting phase transformation capabilities.

Influence of thermo-mechanical and solution annealing treatments on the flow behaviour of 14Cr-15Ni stainless steel

ABSTRACT Thermo-mechanical treatment (TMT) involving cold work and annealing is prevalent in enhancing the mechanical properties of precipitation-strengthened stainless steels. This investigation evaluates the effect of TMT and solution annealing treatment (SAT) on the flow properties of a Ti-added 14Cr-15Ni austenitic stainless steel, which is used as cladding material for fast breeder reactors (FBRs). Comparisons drawn with the solution-annealed (SAT) condition showed that TMT enhances the yield stress more significantly compared to the ultimate tensile strength. Analysis of the work-hardening behaviour suggested that though TMT enhanced the initial work-hardening rate, its microstructure was more susceptible to dynamic recovery. Despite exhibiting lower strength, the SAT process enhanced the ductility at all the investigated test temperatures. Adoption of this TMT process on this material has the potential to enhance the performance of the FBR's cladding.

Effect of thermo-mechanical treatment on cryogenic mechanical properties of a medium-entropy Fe65Co12.5Ni12.5Cr9.5C0.5 alloy produced by the laser-based powder bed fusion

Microstructure and mechanical properties of the Fe65Co12.5Ni12.5Cr9.5C0.5 (in at.%) medium-entropy alloy obtained by the laser-based powder bed fusion (PBF-LB) was investigated in the as-produced condition and after (i) annealing in the interval 800–1100 °C or (ii) cold rolling followed by annealing at 800 °C. The as-produced microstructure was found to be surprisingly stable; noticeable recrystallization occurred only after annealing at 1100 °C. Cold rolling resulted in the formation of typical deformed microstructure, while further annealing led to the formation of a fine-grained recrystallized microstructure. A considerable improvement in cryogenic mechanical properties was obtained after some thermo-mechanical treatments due to the transformation-induced plasticity (TRIP) effect. The cold-rolled alloy had the best cryogenic strength characteristics; yield strength and ultimate tensile strength were found to be 1740 MPa and 2235 MPa, respectively. High strength was combined with a pronounced value of elongation to fracture of 24 %. Detailed analysis of microstructure and corresponding mechanical behavior changes caused by various processing of the as-produced alloy are presented.

The effect of thermomechanical treatment on the electrodeposited Invar alloy for FMM

Fine metal masks (FMMs), which are applied to manufacture next-generation organic light-emitting diode (OLED) displays with ultra-high definition (UHD) or higher, must have thicknesses of <10 μm to eliminate shadow zones. To manufacture FMMs with a thickness of 10 μm or less, a bottom-up electroplating process must be applied. The minimum coefficient of thermal expansion (CTE) of the as-deposited electroplated Invar alloy is 4 ppm; subsequent thermal treatment can lead to a CTE of zero. However, sample conditions such as surface wrinkles and edge curls may appear during this thermal treatment process. The effect of varying treatment parameters, including pressure and temperature, on the shape of the electrodeposited Invar alloy is investigated in this study by performing a thermomechanical treatment that can regulate the ultrathin FMM shape. Depending on the Ni composition, the electrodeposited Invar alloy may exist as a singular α-BCC phase or a mixed γ-FCC phase during electrodeposition. During thermomechanical treatment, a phase transformation occurs from the electrodeposited α-BCC phase to the γ”-FCC phase, and wrinkles occur owing to uneven volume change. Additionally, curls are formed owing to CTE variations according to the ratio of phases from the electrodeposition surface to the final surface varies during the plating process. Based on these results, process conditions that facilitate shape control of ultra-thin electroplated FeNi alloys were proposed.

Effect of post-weld heat-treatment and solid-state thermomechanical treatment on the properties of the AA6082 MIG welded joints

Post-weld heat treatment (PWHT) and solid-state thermomechanical treatment (TMT) via friction stir processing (FSP) have been shown to enhance the mechanical properties of aluminum alloys. The current work investigates the effects of PWHT and TMT on the microstructure and mechanical performance of AA6082-T6 welded butt joints welded using the MIG process. The 5 mm thick AA 6082-T6 plates were joined in butt configuration using MIG welding with ER 5356 filler wire, 120 A current, 0.3 mm/s weld speed, and argon shielding gas at 15 L/min flow rate. PWHT was performed on the MIG welds per the T6 temper procedure. TMT was implemented via FSP using a pinless tool rotating at 800 rpm and traversing speed at 200 mm/min with a 3° tilt angle. Microstructural analysis, hardness mapping, tensile testing, and fracture surface evaluation were utilized to characterize the as-welded, PWHT, and TMT samples. The results demonstrate that both PWHT and TMT significantly refine and homogenize the microstructures of the welded joints. However, the TMT samples displayed superior hardness and tensile strength compared to the as-welded and PWHT conditions. The TMT-processed welds achieved approximately 99% joint efficiency versus only 69% and 85% for the as-welded and PWHT samples. In summary, PWHT and especially TMT via FSP are effective at enhancing the mechanical properties of MIG welded AA6082-T6.

Improvement of shape recovery by controlling the microstructure and mechanical properties in a thermomechanically-treated Fe-based alloy

In this research, the effects of thermomechanical treatment including heavy cold rolling and post-deformation annealing on the improvement of shape recovery in an Fe–9Ni–7Mn (at.%) martensitic alloy were investigated. Experimental results showed that the 80 % cold rolling produced a little fraction of strain-induced austenite phase in the martensitic matrix due to the strain concentration in the microstructure and the temperature rise under deformation. During post-deformation annealing at 590 °C in a dual phase (α+γ) region, a greater fraction of the austenite was introduced in the martensitic matrix such that its amount first increased by increasing the annealing time to 1.8 ks and then decreased at a more time of reversion. The microstructural evolution revealed that the austenite reversion under post-deformation annealing initially occurred by a shear nature at the early steps of reversion and then continued by diffusion. Tensile testing represented a good mixture of a relatively high ultimate tensile strength of ∼780 MPa and proper ductility of ∼8.5 % in the post-deformation annealed (PDA) sample for 0.9 ks. In addition, the shape memory properties were examined under the conditions of cold rolling and post-deformation annealing. The results showed a maximum shape recovery rate of ∼23 % for the cold rolled specimen which increased to ∼50 % after post-deformation annealing for 0.9 ks. The presence of a relatively high amount of retained austenite with proper stability and strength in the microstructure of the PDA sample for 0.9 ks was the reason for achieving the highest value of shape recovery.

EFFECT OF STRUCTURAL-PHASE STATE ON THE DEFORMATION BEHAVIOR AND MECHANICAL PROPERTIES OF NEAR β TITANIUM ALLOY VT22 IN THE TEMPERATURE RANGE 293-823 K

This paper investigates the effect of thermomechanical treatments, including deformation by radial shear rolling or severe plastic deformation by abc pressing with subsequent aging at 773 K, on the structural-phase state, deformation behavior and mechanical properties of commercial near β titanium alloy VT22 (Ti-5Al-5Mo-5V-1Cr-1Fe). The structure of the alloy after radial shear rolling and subsequent aging consists of transformed β grains with a lamellar α + β structure and primary α-phase particles. Severe plastic deformation of the alloy followed by aging causes the formation of a grain-subgrain α + β structure with an average characteristic size of 0.23 µm. It is found that after the thermomechanical treatments, the strength characteristics of the alloy at room temperature increase by ~40% compared to the as-received alloy. The alloy after radial shear rolling and aging retains a 40-20% higher strength in the temperature range of 293-823 K. The strength of the alloy after severe plastic deformation and aging becomes lower than that of the as-received alloy already at a temperature of 773 K. Analysis of creep parameters at 743 K shows that the creep deformation of the alloy in the state after radial shear rolling and aging occurs by the motion of dislocations (glide + climb). The creep deformation of the alloy in the state after severe plastic deformation and subsequent aging is largely contributed to by grain boundary sliding.

Effect of thermo-mechanical treatment with different initial moisture content on bamboo cell walls

Thermo-hydro-mechanical (THM) treatment is an effective way to improve the performance of bamboo. However, to date, research on the impact of moisture content (MC) on THM treatment has been relatively little. This study examined the microstructure and physical and chemical properties of bamboo treated with THM under different initial moisture content conditions. The interaction and influencing relationships among the three were explored to provide a reference for THM in the bamboo industry. According to the results of the Three-point Bending test and Nanoindentation test, it is indicated that humidity has a relatively minor impact on the mechanical performance and micro-mechanical properties of compressed samples. However, Scanning Electron Microscope (SEM) and Mercury Intrusion Porosimetry (MIP) tests have shown that an increase in moisture content effectively improves the uneven deformation of bamboo cell walls during compression, thereby reducing their porosity. However, appropriate moisture content in the experiment affected the softening effect of bamboo and caused slight cracking of the fiber tube during compression. With respect to Fourier Transform Infrared Spectrometer (FTIR) spectroscopy, differences in the initial moisture content can also affect the chemical composition. The X-ray diffraction (XRD) analysis has also shown that the crystallinity of the treated samples was higher than that of the untreated samples. Moisture content has a significant impact on the hygroscopicity and dimensional stability of compressed samples by influencing changes in the chemical composition, microstructure, and crystallinity during thermo-hydro-mechanical treatments. In this experiment, bamboo with a moisture content of 12% had a pronounced softening effect during the hot-pressing process while exhibiting the dimensional stability and low moisture absorption required.

Effects of Thermomechanical Treatments on Tensile Properties of Pure Titanium

In order to increase strength while maintaining the ductility of material, pure titanium was improved through the thermomechanical treatment that combines rolling and heat treatment. The tensile properties of pure titanium treated by rolling and heating were investigated. Test material was JIS Grade 2. This material has a higher corrosion resistance. However, the strength of JIS Grade 2 is lower than that of JIS Grade 3. JIS Grade 2 with high strength while maintaining corrosion resistance is being developed. Techniques for improving the properties of materials with simple compositions are important. Thermomechanical treatment is used as a method for improving material properties. In the present study, the effect of thermomechanical treatment on the material properties of JIS Grade 2 was investigated. Rolling was performed at room temperature and the reduction ratio ranged from 70 to 90 %. The heating temperature was in the range of 300 to 700 °C. Heat treatment from 400 to 500 °C showed an increase in tensile strength while maintaining ductility. When the heat treatment temperature was 450 °C, the strength and elongation were approximately 600 MPa and 25 %. Tensile stress of JIS Grade 4 and the tensile strain of JIS Grade 1 were exhibited.

Influence of elevated temperature and high pressure treatments on structural changes of soy protein concentrate

This study focused on investigating the influence of elevated temperature (95–140 °C) and high pressure treatments (30–6000 bar) in different model process systems on protein-protein interactions, particularly in the domain of high-moisture extrusion (HME) conditions, with a specific emphasis on plant-based proteins. The effects of thermomechanical treatments on soy protein concentrate (SPC) were examined at different scales. Macroscopic analysis showed structural changes only at heat treatments exceeding 95 °C, while the application of high pressure alongside elevated temperature treatments did not result in additional changes. On a microscopic scale, protein melting occurred at temperatures above 95 °C, leading to alterations in tertiary and secondary protein structures. For significant protein denaturation and structure formation, a material-temperature threshold of 120 °C for 60% moistened SPC was required. This study sheds light on the key parameters influencing texturization complexity during elevated temperature and high pressure processes like HME. The findings enhance our understanding of protein texturization mechanisms under these conditions.

Importance of cold rolling and tempering on the microstructure evolution, precipitation behavior and mechanical responses of 9Cr3Co3W1Cu ferritic/martensitic steel

The effects of thermomechanical treatment (cold rolling + tempering) on the microstructure evolution, precipitation behavior, and mechanical properties of the 9Cr3Co3W1Cu martensitic steel (G115) were investigated, by adjusting the cold rolling reduction (0, 20% and 40%), tempering temperature (750 °C and 800 °C) and time (30 min and 120 min). The results indicate that the G115 steel with 20% cold-rolling reduction rate followed by tempering at 800 °C for 30 min exhibits the optimum mechanical response (yield strength (σs) 899 MPa, elongation (δ) 26%), compared with that of 40% cold-rolled (σs 812 MPa, δ 17%) and undeformed steels (σs 670 MPa, δ 15%). The optimum yield strength in 20%-800 °C-30 min steel is attributed to the dislocation strengthening and precipitation strengthening, for the relatively low recrystallization rate and high density Cr23C6 and NbC precipitates, and the good ductility is attributed to the low recrystallization ratio and the uniform microstructure. As a comparison, in 40%-800 °C-30 min steel, a ferrite martensite dual phase structure formed. Due to the hardness difference between the two phases, there may be significant inharmony during the deformation process, leading to premature fracture.

Influence of thermomechanical processing and tempering temperature on tensile flow and work hardening behaviour of India specific reduced activation ferritic martensitic steel

In the present work, an indetailed investigation has been carried out on the effect of thermomechanical treatment (TMT) and tempering temperature on microstructural features, tensile flow characteristics and work hardening behaviour of the India specific reduced activation ferritic martensitic (INRAFM) steel. The flow and work hardening characteristics of the studied steel are described by using the Voce constitutive equation and Kocks- Mecking (K-M) approach respectively in the temperature range of 300–873 K. The steel subjected to TMT and tempering for 90 min at 1033 K shows a refined martensitic lath width, finer size (Cr/W/Fe)23C6 and (V/Ta) (C/N) precipitates with an increment in number density. Furthermore, increase in tempering temperature coarsened the refined structural features. Voce equation closely fits the flow curves at 823 K and 873 K, but shows a slight deviation at temperatures below 773 K. The parameters derived from Voce equation are fairly in good correaltion with the experimental values. The strain hardening rate (θ) vs. true stress (σ) plots portrayed stage-I and stage-III work hardening stages and their corresponding phenomena were discussed. In addition, the effect of TMT and tempering treatment on the work hardening parameters obtained from K-M approach and inter-barrier spacing of the steel were also presented in this study. The work hardening characteristics of the steel signifcantly improved upon TMT due to refinement in microstructural features. The flow stress and work hardening parameters decreases with raise in test temperature due to the dominant effect of dynamic recovery.

Effects of cold rolling and heat treatment on the microstructure and hardness of pure aluminium

The present investigation aims to assess the effects of thermomechanical treatments on both the grain refinement and microhardness of aluminium 1145. Aluminium 1145 is commonly utilized in electronic applications owing to its lightweight features and high thermal and electrical conductivities. Despite its low microhardness, which poses a challenge for such applications, its mechanical properties can be improved by means of thermomechanical treatments such as cold rolling and annealing. The experimental procedure involved casting the sample in an open mould, followed by cold rolling at reductions of 50%, 70%, and 80% from the initial 10 mm thickness. Optical microscopy (OM) was employed to investigate the microstructural changes caused by plastic deformation. A greater degree of deformation was observed along the rolling direction with higher reductions, particularly in the 80% cold-rolled sample, where flattened and elongated grains were evident in the normal plane, whereas a lamellar layered structure was observed in the rolling plane. The Vickers microhardness tester was used to measure the microhardness of the cold-rolled samples. The findings revealed that the microhardness increased with greater rolling reductions, with the 80% cold-rolled sample exhibiting a 72% increase compared with the initial 25HV of the as-cast sample. Moreover, recrystallization was identified at 400 °C, and the grain size increased with increasing annealing temperature and duration. At 450 °C, the grains exhibited equiaxed and finer structures with an average size of 95 μm. The trends in microhardness were aligned with recrystallization and grain growth, as they decreased with increasing annealing temperature and time. Notably, at 450 °C, the microhardness reached 25HV, which was equivalent to the as-cast condition.

Effects of Thermo-mechanical Treatment on the Microstructures and Mechanical Properties of a Medium-Entropy Alloy

Effects of Thermo-mechanical Treatment on the Microstructures and Mechanical Properties of a Medium-Entropy Alloy

Electrochemical characterization of Al–Li alloys AA2099 and AA2055 for aeronautical applications: effect of thermomechanical treatments

Electrochemical characterization of Al–Li alloys AA2099 and AA2055 for aeronautical applications: effect of thermomechanical treatments

Effect of high-dense electropulsing with different energies on the structure and strength of nickel cryorolled to different strains

The effect of thermomechanical treatment, based on combination of isothermal cryorolling at liquid nitrogen temperature to strains ranging from 30 to 90 % and subsequent single electric pulsing with an integral current density Kj up to 1.6 ×104 A2 s / mm4, on the structure and hardness of an initially coarse-grained pure nickel was studied. It is shown that the considered treatment is quite a powerful method to control the Ni structure and strength through grain and grain boundary design. The right chose of conditions of cryogenic straining and electro-heat action give ability to high efficient production of abnormally and partially work-hardened sheets with light tuning of crystallite size and fractions of recrystallized grains and high angle boundaries, in particular, the fine-grained sheet with a grain size of about 3 μm and 50 % fraction of the twin boundaries.

Effects of thermomechanical treatments on Cu–Al–Mn Shape Memory Alloys

In this paper, the authors, building on the established state-of-the-art knowledge, explore the effects of thermomechanical treatments on the Shape Memory Effect (SME) and damping performance of the Cu–Al–Mn Shape Memory Alloys (SMA). Specifically, to explore the potential of application of this SMA in the form of sheets, for the purpose of designing lightweight structures with high damping performance. The casting and the thermomechanical treatment process were fully laid out in the paper. The characterization of the material in terms of chemical composition and microstructure was performed through optical microscopy and SEM coupled with EDX analysis. The temperature-induced phase transformation behavior of the alloy was explored using DSC. The damping performance was quantified through the loss factor which was measured at different levels of static tensile preload using a DMA machine. The alloy has shown significant workability which permits the fabrication of sheets. However, the material displays high sensitivity to oxidation due to a combined effect of impurities and the hot-rolling process necessary for obtaining thin SMA sheets. Nonetheless, the alloy shows competitive damping performance with respect to commercially available NiTi SMA.

Creep deformation behaviour of thermomechanically treated India specific reduced activation ferritic martensitic steel

In the present work, the influence of thermomechanical treatment (TMT) on microstructural evolution and creep deformation behaviour of India specific reduced activation ferritic martensitic (INRAFM) steel was investigated. Firstly, the TMT was carried out on INRAFM steel by reducing its thickness to 25% at warm rolling temperature (973 K), followed by tempering for 90 min at 1033 K. The resultant microstructural characteristics were compared with those attained in normalized and tempered (N+T) condition. TMT treated steel shows a refinement in lath structure with an increment in population of finer M23C6 precipitates along the hierarchal PAG/packet/block boundaries and MX carbonitrides in the intralath region. After TMT, creep tests were performed on the steel over the stress range of 200–300 MPa at temperature of 823 K. The rupture time of the steel significantly increased upon TMT, due to refinement in microstructural features that enhanced the creep resistance. Dependence of minimum creep rate on applied stress obeys Norton's power law and the stress exponent values indicated the deformation mechanism as dislocation creep. Modified Monkman-Grant relation shows a good relation between rupture time/strain to failure with minimum creep rate. Thereafter, the effect of TMT on the transient, secondary and tertiary creep behaviour was also examined and presented in this work. The TMT treated steel shows lower rate of exhaustion, higher threshold stress and prolonged tertiary region.

Resistance of Cunninghamia lanceolata Wood Against White-rot Fungi by Using Thermo-Mechanical Treatment

Heat treatment is an effective method to enhance the biological durability of wood without the use of preservatives. This study aims to analyze the effect of thermo-mechanical treatment on the durability of wood against the attack of some white rot fungi. The central composite design (CCD) method with the help of Design Expert 12.0 software was used to investigate the effects of temperature, compression time, and compression ratio on the white rot fungus resistance of Cunninghamia lanceolata wood. The obtained results revealed that the thermo-mechanical treatment of Cunninghamia lanceolata samples showed improved antifungal resistance compared to the untreated ones. After 4 months of testing in laboratory conditions, all wood samples with heat-mechanical treatment showed better resistance to fungi. Moreover, the different temperatures, compression ratios, and compression time bring out the different mass loss rates. The obtained results indicate that the wood samples modified at the temperature of 200°C, and 0.6 min/mm thickness combined with the compression ratio ranging from 40÷42% gave the lowest loss rate. Particularly, the resistance test for Lentinula edodes gives the best results when the wood compression time is at 0.7 min/mm thickness. Also, this work would provide a scientific and theoretical basis for the relationship between thermo-mechanical treatment and the biological durability of Cunninghamia lanceolata wood.

Effect of Thermomechanical Treatment on the Micro-hardness and Crystallization Behavior of an Amorphous Zr65.5Ni16Cu8.5Al10 Alloy

Effect of Thermomechanical Treatment on the Micro-hardness and Crystallization Behavior of an Amorphous Zr65.5Ni16Cu8.5Al10 Alloy