Modina Iuliia M, Dyakonov Grigory S, Stotskiy Andrey G, Yakovleva Tatyana V, Semenova Irina P
Laboratory of Advanced Technologies, "Higher Engineering School of Aerospace Technologies" Center, Ufa University of Science and Technology, 32 Zaki Validi St., 450076 Ufa, Russia.
Materials (Basel). 2023 Feb 3;16(3):1318. doi: 10.3390/ma16031318.
In this work, the strength properties and impact toughness of the ultrafine-grained (UFG) Ti-6Al-4V titanium alloy produced by severe plastic deformation (SPD) in combination with upsetting were studied, depending on the direction of crack propagation. In the billets processed by equal-channel angular pressing (ECAP), the presence of anisotropy of ultimate tensile strength (UTS) and ductility was observed, conditioned by the formation of a metallographic and crystallographic texture. At the same time, the ECAP-processed UFG alloy exhibited satisfactory values of impact toughness, ~0.42 MJ/m. An additional upsetting of the ECAP-processed billet simulated the processes of shape forming/die forging and was accompanied by the development of recovery and recrystallization. This provided the "blurring" of texture and a reduction in the anisotropy of UTS and ductility, but a difference in impact toughness in several directions of fracture was still observed. It is shown that texture evolution during upsetting provided a significant increase in the crack propagation energy. The relationship between microstructure, texture and mechanical properties in different sections of the material under study is discussed.
在本研究中，对通过严重塑性变形（SPD）结合镦粗制备的超细晶粒（UFG）Ti-6Al-4V钛合金的强度性能和冲击韧性进行了研究，研究内容与裂纹扩展方向有关。在通过等通道转角挤压（ECAP）加工的坯料中，观察到极限抗拉强度（UTS）和延展性的各向异性，这是由金相和晶体织构的形成所决定的。同时，经ECAP加工的UFG合金表现出令人满意的冲击韧性值，约为0.42 MJ/m²。对经ECAP加工的坯料进行额外的镦粗模拟了成形/模锻过程，并伴随着回复和再结晶的发展。这使得织构“模糊化”，UTS和延展性的各向异性降低，但在几个断裂方向上的冲击韧性仍存在差异。结果表明，镦粗过程中的织构演变显著提高了裂纹扩展能量。讨论了所研究材料不同截面中微观结构、织构和力学性能之间的关系。
