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研究了电子束快速成形TI6AL4V和Ti45Al7Nb合金混合粉末的特点,得到了成分均匀的Ti22Al3.5Nb2V合金。利用光学显微镜、扫描电镜、电子探针等手段,研究了成形试样的内部组织,并测试了不同组织区域的显微硬度。结果表明:TI6AL4V和Ti45Al7Nb合金混合粉末在电子束成形后,成分均匀,组织具有沉积态特征,包括板条马氏体区和α_2+β两相区,板条马氏体区位于成形零件顶部10个熔覆层厚度,在成形过程中,受再热循环的影响,已凝固形成的马氏体不断分解形成α_2+β两相区,α_2为短棒状,β分布于α_2相之间,在成形件底部,部分α_2相发生等轴化。显微硬度测试结果显示,马氏体区硬度明显高于α_2+β两相区。拉伸结果显示,抗拉伸强度为1214.3MPa,延伸率达到18%。
The characteristics of Ti6Al4V and Ti45Al7Nb alloy powders by electron beam rapid prototyping were studied. Ti22Al3.5Nb2V alloy with uniform composition was obtained. Using optical microscope, scanning electron microscopy, electron probe and other means, the internal structure of the formed sample was studied and the microhardness of different tissue regions was tested. The results show that the composition of TI6AL4V and Ti45Al7Nb alloy powder is uniform after e-beam forming, and the microstructure has the characteristics of deposition, including lath martensite zone and α_2 + β two-phase zone. The lath martensite zone is located at the top of the forming part 10 The thickness of the cladding layer is affected by the reheat cycle during the forming process. The solidified martensite continuously decomposes to form the α_2 + β two-phase region, the α_2 is short rod, the β is distributed between α_2 phase, Part of the bottom part of the α_2 phase equiaxed. The results of microhardness test show that the hardness of martensite is obviously higher than that of α_2 + β. Tensile results show that the tensile strength of 1214.3MPa, elongation of 18%.