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针对具有特殊非线弹性变形行为的高强度低模量Ti-24Nb-4Zr-8Sn(质量分数,%,简称Ti2448)医用钛合金,采用光学浮区生长法制备出3种典型取向的低指数单晶,研究其塑性变形行为。结果表明,Ti2448单晶合金的室温拉伸性能表现出明显的各向异性,<100>取向、<110>取向和<111>取向单晶的抗拉强度分别为650、642和889 MPa,延伸率分别约为73%、22%和13%;单晶合金的室温拉伸塑性变形机制以滑移为主,<100>取向单晶开动的滑移系统为(112)[111]、(112)[111]、(112)[111]和(112)[111],<110>取向单晶开动的滑移系统为(211)[111]和(211)[111],<111>取向单晶开动的滑移系统为(211)[111];<100>取向、<110>取向和<111>取向单晶合金的拉伸样品断口形状分别呈现矩形状、鸭嘴状和三角状,断裂面与拉伸方向的夹角均约为55°,断口均呈现韧性断裂特征。
Aiming at the high strength and low modulus Ti-24Nb-4Zr-8Sn (Ti2448) titanium alloy with special nonlinear elastic deformation behavior, three kinds of typical index low index single Crystal, to study its plastic deformation behavior. The results show that the tensile properties of Ti2448 single crystal alloys show obvious anisotropy at room temperature. The tensile strengths of <110>, <110> and <111> oriented single crystals are 650, 642 and 889 MPa, respectively The rates of tensile and plastic deformation were about 73%, 22% and 13%, respectively. At room temperature, the plastic deformation mechanism of the single crystal alloy was mainly slippery. The sliding systems of <100> (111) and (211) [111], (111) and (111) [111], and [112] (211) [111]. The fracture shapes of <100>, <110> and <111> oriented single crystal alloys show a rectangular shape, a duckbill shape and a triangular shape, respectively, The angle between the plane and the stretching direction is about 55 °, and the fracture shows the ductile fracture characteristics.