激光立体成形Ti-6Al-4V时效态合金显微组织结构研究

Study on Microstructure of Aging Laser Solid Forming Ti-6Al-4V Alloy

利用激光立体成形技术制备了Ti-6Al-4V(TC4)合金,随后对其进行退火和固溶时效处理.分别利用OM、SEM和STEM在不同尺度对时效态TC4钛合金的显微组织、结构和元素分布进行了研究.结果表明:时效态TC4钛合金晶界处存在连续分布的初生α相,晶内为网篮组织,由交叉分布的板条状α相组成,其宽度约为2μm;板条状α相中残留的β相以网状结构弥散分布在其内部;相邻板条状α相之间存在β相和次生α相组成的两相区,α相富含Al元素,β相富含V元素,验证了两相之间具有(0001)α//(110)β、[1120]α//[111]β的取向关系.

Ti-6Al-4V(TC4)alloy was prepared by laser solid forming technology,and then subjected to annealing,solid solution and aging treatment in sequence.The microstructure and the element distribution of the aged TC4 titanium alloy were studied by OM,SEM and STEM.The results show that there is a continuous primaryαphase at the grain boundary of the aged TC4 titanium alloy,the microstructures inside the grain present basket-weave structure,mainly consisting of lath-likeα-Ti with a width of 2μm.The residualβphase with network structure is dispersed in the interior of the lath-likeαphase.Between two adjacent lath-likeαphases,there is a two-phase region composed ofβphase and secondaryαphase.Theαphase is rich in Al element and theβphase is rich in V element.The orientation relationship between these two phases has been verified to be(0001)α∥(110)βand[11 2 0]α∥[1 11]βby SADP analysis.