激光能量密度对激光选区熔化Cu-Al-Ni-Ti合金相对密度、微观组织和力学性能的影响  

Effect of Laser Energy Density on Relative Density, Microstructure and Mechanical Properties of Cu-Al-Ni-Ti Alloy Fabricated by Selective Laser Melting

作　　者：朱文志 党明珠 田健 魏青松[1] ZHU Wenzhi;DANG Mingzhu;TIAN Jian;WEI Qingsong(State Key Laboratory of Material Processing and Die&Mould Technology,Huazhong University of Science and Technology,Wuhan 430074)

机构地区：[1]华中科技大学材料成形与模具技术国家重点实验室,武汉430074

出　　处：《机械工程学报》2020年第15期53-64,共12页Journal of Mechanical Engineering

基　　金：国家自然科学基金青年基金(51701078);武汉市应用基础前沿(2018010401011281);中国博士后基金面上(2018M632846)资助项目。

摘　　要：采用激光选区熔化技术(Selective laser melting,SLM)成形制备了不同工艺参数下Cu-Al-Ni-Ti铜基形状记忆合金试样。用排水法测试了块体试样的相对密度,对试样进行了显微组织分析和热分析,测试了拉伸试样在不同温度下的力学性能和测试试样的形状记忆性能,研究了激光能量密度对相对密度、显微组织和常温力学性能的影响规律。结果表明:块体试样的相对密度随激光能量密度的增大先增大再减小,试样的相对密度最大值达99.9%;当激光能量密度适中时(107J/mm3),熔化道连续且无明显缺陷,激光能量密度过低或者过高,试样会产生熔化道不连续或者球化等缺陷;拉伸试样的常温拉伸性能随激光能量密度的增大先增大再减小,常温下试样最大抗拉强度和延伸率分别为541MPa和7.63%。在300℃下试样的抗拉强度提升至最大为611MPa,延伸率提升至10.78%。试样的马氏体相变开始温度Ms约为83℃,结束温度Mf约为40℃,形变回复率接近90%。Cu Al-Ni-Ti copper-based shape memory alloy samples are fabricated by selective laser melting(SLM) with different processing parameters. The relative density of bulk samples is measured by drainage method. The microstructure and thermal analysis of the samples are carried out. The mechanical properties of the tensile samples at different temperatures and the shape memory properties of the samples are tested and the effect of laser energy density on the relative density, microstructure and mechanical properties at room temperature are studied. The results show that the relative density of bulk samples increases first and then decreases with the increase of laser energy density and the maximum relative density of bulk samples exceeds 99.5%. When the laser energy density is moderate(107 J/mm3), the melting channel is continuous and without obvious defects. If the laser energy density is too low or too high, the melting channel of the sample will be discontinuous or spheroidization. The tensile properties of tensile samples at room temperature first increase and then decrease with the increase of laser energy density. The maximum tensile strength and elongation of the samples at room temperature are 541 MPa and 7.63%, respectively. The tensile strength and elongation of the samples at 300 ℃ increased to 611 MPa and 10.78%, respectively. The starting temperature of martensitic transformation is about 83 ℃ and the ending temperature is about 40 ℃. The deformation recovery rate is close to 90%.

关 键 词：铜基形状记忆合金 激光选区熔化 相对密度 微观组织 力学性能 形状记忆性能 

分 类 号：TG146[一般工业技术—材料科学与工程]