采用(Ti/Ni/Cu)_f多层箔钎焊C/C复合材料与TiAl合金

Brazing of C/C Composite to TiAl Alloy Using(Ti/Ni/Cu)_f Multi-foil Filler

采用（Ti/Ni/Cu）f多层箔状钎料进行C/C复合材料与TiAl合金的钎焊,实现了良好的界面结合,保证了接头的高温力学性能。研究结果表明:钎焊过程中,首先在Ti/Ni界面处接触反应形成低熔共晶液相,Cu元素的溶解促进了钎料的完全熔化和扩散,接头组织一般为C/C/TiC/Al2（Cu,Ni）Ti3C/Ti（Cu,Ni）+Al（Cu,Ni）2Ti/Al（Cu,Ni）Ti+Ti3Al/TiAl,Ti（Cu,Ni）基体相和球状弥散分布的Al（Cu,Ni）2Ti相是钎缝的主要组成部分。当钎焊温度较低或者保温时间较短时,由于钎缝中生成了大量的脆性Ti2Ni相,降低了接头的力学性能;当钎焊温度较高或保温时间较长时,C/C复合材料母材界面处开裂,且TiC层从母材脱落,也削弱了接头的抗剪强度。当钎焊温度为980℃,保温时间为10 min时,C/C复合材料与TiAl合金的接头室温抗剪强度达到最大值18 MPa,600℃时接头的高温抗剪强度达到22 MPa。

C/C composite is brazed to TiAl alloy using（Ti/Ni/Cu）f multi-foil filler. The brazing joint displayed reliable interface bonding and excellent mechanical properties under high temperature. The research showed during brazing process, low-melting-point eutectic liquid-phase structure is firstly formed through the contact reaction at the Ti/Ni interface, then complete melt and diffusion of the filler occurred afterwards with Cu element dissolving. General microstructure of the joint show as follows: C/C/TiC/Al2（Cu,Ni）Ti3 C/Ti（Cu,Ni）+Al（Cu,Ni）2 Ti/Al（Cu,Ni）Ti+Ti3 Al/TiAl. The Ti（Cu,Ni） matrix phase and spheroidal dispersion of the Al（Cu,Ni）2 Ti phase constitute the main components of the joint. A mass of fragile Ti2 Ni phase caused by lower brazing temperature and shorter holding time reduced mechanical property of the joint. Higher brazing temperature and longer holding time made the interface structure of the C/C composite crack and TiC separate from the substrate, leading to a drop in shear strength of the joint. When the joint of the C/C composite and the TiAl alloy is brazing at 980 ℃ for 10 min, the shear strength reached the maximum 18 MPa at room temperature, and increased to 22 MPa at high temperature about 600 ℃.