不同锻造工艺对TA15棒材组织性能影响

Studies on the influences of forging processes on the microstructures and properties of TA15 rods

采用自由锻和径锻工艺,分别制备出直径Φ200 mm和Φ100 mm的两支TA15钛合金锻棒,研究了锻造工艺对TA15锻棒组织和力学性能的影响。结果表明,两种TA15锻棒不同位置的金相组织有明显差异,径锻棒心部初生α相占比高,初生及次生α相均呈现不规则变形组织形貌,说明Φ100 mm锻棒中心发生变形。两支锻棒的α相含量从心部到边部逐渐减少,β转变组织含量逐渐增多。退火后径锻棒的组织内存在大量块状α相和细小再结晶晶粒,而自由锻锻棒组织无明显变化。经过径锻变形后,锻棒的边部室温抗拉强度、面缩和冲击性能提升。细长的片层状组织提供了更多α/β相界面,促进了高温扩散,使得自由锻锻棒的高温力学性能低于径锻棒。

TA15 rods with the diameter of 100 mm and 200 mm were produced by free forging and radial forging respectively.In this study,the effects on the microstructures and mechanical properties of TA15 rods were investigated.It is shown that there are dramatic differences in the microstructures at different positions of two rods.Deformation occurs in the center of the radial forged rods with a considerable amount of primaryαphase in the microstructure,ascertained by the irregular and deformed appearance of the primary and secondaryαphases.The content ofαphase in two rods is lowered from the center to the edge,while the amount ofβtransformation phases increase.The phase morphology change in the free forged rod is negligible after annealing.However,a great quantity of blockyαphase and tiny recrystallized grains appear in the microstructure of radial forged rod after annealing.The tensile strength,area reduction and impact energy of the rod are increased by radial forging.The long and thin lamellar structures provide more interfaces ofα/βphases,promoting fast diffusion at high temperature and leading to the results that the high-temperature properties of free forged rod are worse compared to that of the radial forged rod.