Phase transformations during highpressure torsion hpt. The ascast nondeformed alloys contained the fine particles of mg32al,zn49. Abstractgermanium has been processed by highpressure torsion hpt under a nominal pressure of 24 gpa at room temperature and cryogenic temperature. However, the cementite phase was barely noticeable as shown in fig.
Phase transformation during highpressure torsion hpt, a severe plastic deformation method as schematically shown in fig. Highpressure torsion driven phase transformations in cu. During the annealing, grains grew in a continuous manner. Phase transformation of germanium by processing through high. Highpressure phase transformations under severe plastic. A systematic study on the phase transformation of niti shape memory and superelastic alloys subjected to severe plastic deformation spd high pressure torsion hpt technique has been carried out. Hydrostatic pressure is a significant parameter influencing the evolution of microstructure and phase transformations in the highpressure torsion hpt process. High pressure torsion leads to the phase transformations in the studied ti4 wt. Phase transformations in tife alloys induced by high. Highpressure torsion deformation induced phase transformations.
Pdf allotropic phase transformation of pure zirconium by. Levitas2 1department of mechanical engineering, isfahan university of technology, isfahan 8415683111, iran 2iowa state university, departments of aerospace engineering, mechanical engineering, and material. In this study, severe plastic deformation spd via the highpressure torsion hpt method is applied to the mgh2tih2 system to synthesize metastable hydrides. Highpressure phase transformations under severe plastic deformation by. In conclusion, the obtained results show that highpressure torsion applied to cualni shape memory alloys in both austenitic. Pdf phase transformations in mgh2tih2 hydrogen storage. Phase transformation in niti shape memory and superelastic. Phase transformations during highpressure torsion hpt in titanium, cobalt and graphite.
Pure zr is processed by highpressure torsion hpt at pressures in the range of 140 gpa. The designated alloy after casting was processed further by highpressure torsion hpt to improve its hardness via the introduction of nanograins, dislocations and orderdisorder transformation. Pdf real hydrostatic pressure in highpressure torsion. Ti does not appear after uniaxial compression at the same pressure, without torsion. However, they are poorly characterized, and phase transformation pressure and pressure hysteresis vary drastically in experiments of. High pressure phase transformations play an important role in the search for new materials and material synthesis, as well as in geophysics. Present study investigatesthe effect of the ultra fine grained ufg structure induced by hpt deforma tion on the phase transformations in ti15 mo phwdvwdeoh ti alloy. Phase transformations in a cucr alloy induced by high. Si100 wafers were subjected to severe plastic deformation under a pressure of 24 gpa using highpressure torsion hpt. Allotropic phase transformation of pure zirconium by high. Singlecrystalline si100 wafers were processed by hpt under a pressure of 24 gpa at room temperature. Effect of contact sliding biao feng1,a and valery i.
Here we present a study of the interphase boundary structure, grain size evolution and intermetallic phase formation during hpt deformation of a nanocrystalline alti composite. In this study, severe plastic deformation was successfully imposed on barium titanate ceramic powders by highpressure torsion. Phase transformations in almgzn alloys during high. Cner, kyushu university molecular photoconversion devices division. Several elements were processed by highpressure torsion and phase transformations were investigated. Pdf allotropic phase transformation of pure zirconium by high. Phase transformations of some humerothery phases electron compounds to others in a coppertin system subjected to highpressure torsion were detected in our previous work b.
Coupled phase transformations and plastic flows under. Introduction in all applications of 316l steel the mechanical strength is an important factor. Phase transformation and nanograin refinement of silicon. Levitas2,b 1department of aerospace engineering, iowa state university, ames, iowa 50011, usa 2departments of aerospace engineering, mechanical engineering, and material science and engineering. This study reports the occurrence of grain growth in nanocrystalline al2o3 by spd processing via highpressure torsion hpt due to a phase transformation from. Highpressure torsion deformation induced phase transformations and formations. Pdf phase transformations in tife alloys induced by. Pdf phase transformations during highpressure torsion.
Highpressure torsion hpt deformation of multiphase metallic systems produces a high density of interfaces and leads to atomic mixing between the constituent phases. Annealing behavior in a highpressure torsionprocessed fe. Severe plastic deformation by the high pressure torsion hpt leads to the strong grain refinement in tife alloys. The effect of the ultrafine grained ufg structure achieved by hpt on the phase transformations was studied by differential scanning calorimetry. Structural and mechanical properties of tico alloys treated by. After homogenization in the one phase austenitic barea of cuealeni phase diagram and quenching, the. Significant grain refinement with grain size of 100 nm was achieved even after 14 of hpt rotation. The solution treated ti15mo alloy was deformed by high pressure torsion hpt at room temperature. A tetragonaltocubic phase transformation occurred, and the fraction and stability of the cubic phase increased by straining because of the formation of nanograins. In situ observation of the phase transformations in ti15mo. Highpressure torsion hpt, as schematically shown in fig.
Phase transformations induced by high pressure torsion hpt at room temperature in two samples of the cu0. Pdf hydrostatic pressure is a significant parameter in fluencing the evolution of microstructure and phase transformations in the highpressure. Production of nanograined intermetallics using highpressure. Real hydrostatic pressure in highpressure torsion measured by. Meanwhile, the phase transformation proceeded, resulting in the formation of more ferrite and m23c6 carbide. The effect of highpressure torsion hpt on the structural and phase transformations in a new eutectic aluminium alloy 94. Pdf highpressure torsion of titanium at cryogenic and. Severe plastic deformation by highpressure torsion hpt changes the composition of phases in the cu4. Fabrication of nanograined silicon by highpressure torsion. The structure, phase composition, and their thermal evolution were studied in case of ternary alznmg alloys before and after highpressure torsion hpt in bridgman anvils. Pdf pure zr is processed by highpressure torsion hpt at pressures in the range of 140 gpa.
Pdf microstructure, phase composition and hardness. Plastic deformation of batio 3 ceramics by highpressure torsion and changes in phase transformations,optical and dielectric properties. This chapter examines the various publications describing the experimental studies of the effect of hpt on the mechanical behaviors and alterations of microstructural. Microstructural evolution and phase transformation in. Grain size effect on allotropic phase transformations. Pdf graphite to diamondlike carbon phase transformation. Pdf highpressure torsion driven phase transformations. This suggests that the transformation kinetics are notably increased as compared with the kinetics of pressureinduced transformation.
Coupled phase transformations and plastic flows under torsion at high pressure in rotational diamond anvil cell. The tife alloys are quite important among various tibased alloys doped with bstabilisers. A broad photoluminescence peak centered at about 650 nm appears due to the reverse transformation of siiiisixii nanograins and the reduction of number of defects in sii nanograins. Structural and phase transformations in a new eutectic alcamnfe. Unlimited viewing of the articlechapter pdf and any associated supplements and figures. The goal of this work is to investigate the com bination of displacive austenite4martensite and diffusive decomposition of supersaturated solid solution phase transitions in two different cuealeni shape memory alloys under the in. Understanding well the potential of hpt to stabilize high.
Coulomb and plastic friction are combined and take into account variable parameters due to pt. Phase transitions during high pressure torsion of cuco alloys. Highpressure torsioninduced phase transformations and. The goal of this work is to investigate the combination of displacive austenite4martensite and diffusive decomposition of supersaturated solid solution phase transitions in two different cuealeni shape memory alloys under the influence of highpressure torsion. Starting materials can be either coarsegrained multiphase alloys, a mixture of different elemental. Impact of tio2ii phase stabilized in anatase matrix by highpressure torsion on electrocatalytic hydrogen production. Results are obtained for weaker, equalstrength, and. Plastic deformation of batio3 ceramics by highpressure. Impact of tio2ii phase stabilized in anatase matrix by. Xray diffraction and raman analysis revealed that the hptprocessed samples were.
Based on the tkd result, the volume fractions of ferrite and m23c6 increased remarkably to 23% and 3. In this study, severe plastic deformation spd via the high. After a certain strain, the dynamic equilibrium establishes between defects production by an external force and their relaxation annihilation. While mgh2 transforms to a highpressure orthorhombic.
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