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Metallic Biomaterials
Published in Joseph D. Bronzino, Donald R. Peterson, Biomedical Engineering Fundamentals, 2019
Joon B. Park and Young Kon Kim
controlled composition and thermomechanical processing techniques. Addition of alloying elements to titanium enables it to have a wide range of properties: (1) Aluminum tends to stabilize the α-phase, that is, increase the transformation temperature from α-to β-phase (Figure 28.4). (2) Vanadium stabilizes the β-phase by lowering the temperature of the transformation from α to β.
Hot Rolling System Design for Advanced High Strength Steels (AHSSs)
Published in Jingwei Zhao, Zhengyi Jiang, Rolling of Advanced High Strength Steels, 2017
Thermomechanical processing is defined as a hot deformation schedule (rolling, forging, extrusion, etc.) designed for the purpose of achieving a predetermined microstructure in austenite prior to transformation to ferrite (DeArdo 1995). The microstructure of austenite can be described by the parameters: grain size, composition, presence or absence of microalloy precipitates, degree of recrystallization and texture. Comparison of conventional and contemporary techniques for hot rolling of steel is shown schematically in Figure 9.5.
Surface and bulk modification techniques to mitigate silt erosion in hydro turbines: a review of techniques and parameters
Published in Surface Engineering, 2022
Thermomechanical processing is a combination of mechanical (plastic deformation including forging, rolling, compression, etc.) and thermal processes (various heat treatments) to modify the microstructure and the mechanical properties. Thermomechanical processing has been used to improve the erosion (slurry and cavitation erosion) performance of various steel in literature. Neeraj and co-researchers performed thermomechanical processing on SAILMA grade HSLA steel to improve the erosion resistance [95]. In this study, they performed warm multidirectional forging at a strain rate of 10 s−1 and intercritical annealing at 740°C for 10 min and water quenching. The warm multidirectional forging led to the refinement in ferrite-pearlite microstructure while annealing and water quenching transformed the microstructure into ferrite-martensite dual-phase microstructure. This microstructural evolution led to a better combination of hardness, tensile strength, toughness, and work hardening which subsequently improved the slurry erosion resistance.
Computational Investigation of Effects of Grain Size on Ballistic Performance of Copper
Published in International Journal for Computational Methods in Engineering Science and Mechanics, 2018
Ge He, Yangqing Dou, Xiang Guo, Yucheng Liu
Inspired by Guo's work, in this work we will continue to use Guo's model to investigate the effects of grain size on ballistic performance of Cu. It is well known that the strength and ductility of a metallic material can be significantly increased by reducing its grain size either through thermomechanical processing or by severe plastic deformation methods. However, there is very litter research that has discussed how copper specimens with different grain sizes perform during the high-speed impact and penetration process. The present work intends to fill this gap by comparing the impact response and penetration behavior of Cu with four representative grain sizes, as well as with those of Cu strengthened by the NT regions. Cu specimens and grain sizes selected for this study include CG Cu with a grain size about 90 µm, regular Cu with a size about 30 µm, FG Cu with a size about 890 nm, and UG Cu with a size about 200 nm. Constitutive relations of the Cu specimens were described by JC model and the material constants for all involved Cu specimens had already been calibrated by the authors and other investigators.
Microstructural evolution and grain-growth kinetics of Al0.2CoCrFeNi high-entropy alloy
Published in Philosophical Magazine Letters, 2021
Srinivas Dudala, Chenna Krishna S, Rajesh Korla
It is well established that the room-temperature mechanical properties of any structural material strongly depends on the average grain size, the size distribution, and the nature of the grain boundaries [1]. Thermomechanical processing can enhance both strength and ductility by refining the grains via recrystallization processes. The grain size then increases via grain growth during subsequent annealing at high temperatures. During grain growth, grain-boundary migration occurs by a local shuffling of atoms across the grain boundary, which is assisted by grain-boundary diffusion. As grain-boundary migration and grain-boundary diffusion involve similar mechanisms, similar activation energies[2–6] will be involved.