异质层状钛合金增材构件微观组织与力学性能  

Microstructure and mechanical properties of heterogeneous layered titanium alloy components fabricated via additive manufacturing

作　　者：郭顺[1,2] 徐俊强 杨东青 顾介仁 周琦[1,2] GUO Shun;XU Junqiang;YANG Dongqing;GU Jieren;ZHOU Qi(School of Materials Science and Engineering,Nanjing University of Science and Technology,Nanjing 210094,China;Key Laboratory of Controlled Arc Intelligent Additive Manufacturing Technology,Nanjing University of Science and Technology,Nanjing 210094,China)

机构地区：[1]南京理工大学材料科学与工程学院,南京210094 [2]南京理工大学受控电弧智能增材技术工信部重点实验室,南京210094

出　　处：《复合材料学报》2022年第12期6017-6027,共11页Acta Materiae Compositae Sinica

基　　金：国家自然科学基金青年基金(52105367);江苏省博士后资助计划(2021K591C)。

摘　　要：采用双丝等离子实现了TC4与TA2交替沉积的异质层状钛合金构件的增材制造,构件具有良好的沉积形貌及力学性能。采用了OM、SEM、背散射电子衍射技术(EBSD)、XRD等方法对构件进行了微观组织表征,并结合显微硬度和压缩性能测试了其力学性能。研究结果表明:TA2和TC4区域主要组织分别是由片层α相和α+β的网篮组织/集束组织组成。各区域晶粒沿着热流反方向凝固生长,TC4区域与TA2区域的晶界特征和晶体取向具有相似规律,但由于异质材料相生长差异,层与层之间β相晶粒生长方向发生改变,TC4区域的原始β相会沿着已沉积TA2区域晶粒某一择优取向生长,进而限制了β相连续生长为粗大柱状晶。层状结构中TC4区域的硬度明显高于TA2区域,并沿着沉积方向硬度呈现增加的趋势。增材构件沿着不同方向具有接近的抗压强度,近2.0 GPa,但是TC4和TA2交替形成的层状特殊结构,其沿着沉积方向具有高的断裂应变(0.33),沿着扫描方向具有高的屈服强度(1133 MPa)。The additive manufacturing of heterogeneous layered titanium alloy is realized by the alternating deposition of TC4 and TA2 using a double wire plasma system.The components have good deposition morphology and mechanical properties.OM,SEM,backscattered electron diffraction technique(EBSD),XRD etc.were used to analyze the microstructure,mechanical properties were tested with microhardness and compression properties.The results show that TA2 and TC4 regions are mainly composed of lamellaeαphase andα+βphase of basketweave and colonies structure.The grains in each region grow in the opposite direction of heat flow.The grain boundary characteristics and crystal orientation of TC4 region and TA2 region have similar laws,but due to the differences of phase growth of heterogeneous materials,the growth direction ofβphase has changed between different layers,and the originalβphase growth direction of TC4 region will grow along a preferred orientation of the deposited TA2 region,which limits the phenomenon of continuous growth ofβphase into coarsened columnar crystal.In the layered structure,the hardness of TC4 region is significantly higher than that of TA2 region,and the hardness increases along the deposited direction.The component has close compressive strength along different directions,nearly 2.0 GPa,but the special layered structure formed alternately by TC4 and TA2 has high fracture strain(0.33)along the deposited direction and high yield strength(1133 MPa)along the travel direction.

关 键 词：异质钛合金 层状材料 增材制造 微观组织 力学性能 

分 类 号：TG456.2[金属学及工艺—焊接]