激光同轴送粉增材制造TiAl合金的性能

Properties of TiAl Alloy Prepared by Additive Manufacturing with Laser Coaxial Powder Feeding

将Ti-48Al-2Cr-2Nb合金粉和铌粉进行机械混合,然后采用激光增材制造工艺成功制备出γ-TiAl合金样品,研究了激光功率、扫描速率和送粉量对沉积成形的影响规律,分析了沉积层的显微组织、相组成、断口形貌及沉积层的硬度分布。研究结果表明:随着激光功率增大,沉积层宽和层高均增大;随着扫描速率增大,沉积层宽和层高均减小;随着送粉量增大,沉积层的宽度增大,沉积层的高度基本不变;最佳工艺参数下得到的沉积试样成形良好,无冶金缺陷存在,沉积层由大量γ相和少量α_2相组成;沿沉积试样Z方向的室温压缩屈服强度为905 MPa,抗压强度为1542 MPa,压缩率14.7%,抗拉强度为425 MPa,断后伸长率为3.3%;压缩试样和拉伸试样的断口均为准解理断口。

The alloy powders containing Ti-48 Al-2 Cr-2 Nb and niobium are mechanically mixed,andγ-TiAl alloy samples are successfully prepared with the laser additive manufacturing technique.The influence rules of laser power,scanning speed and powder feeding amount on deposition forming are studied,and the microstructure,phase composition,fracture morphology and hardness distribution of the deposited layer are analyzed.The research results indicate that the width and height of the deposited layer increase with the increase of laser power.With the increase of the scanning speed,the width and height of the deposited layer decrease.With the increase of powder feeding amount,the width of the deposited layer increases and the height of the deposited layer is basically unchanged.The deposited samples obtained under the optimum technology parameters are well formed and have no metallurgical defects.The deposited layer consists of a large number ofγphases and a small amount ofα2 phases.The compressive yield strength,compression strength and compression ratio are 905 MPa,1542 MPa and 14.7%respectively along the Z direction of deposited specimen at room temperature.The tensile strength and elongation are 425 MPa and 3.3%,respectively.The fractures of compressive specimen and tensile specimen are both quasi-cleavage fractures.