电场作用下Ti/TiAl连接及力学性能

Effect of current field on Ti/TiAl interface and mechanical performance

运用电场激活压力辅助合成工艺(FAPAS)实现了TiAl的燃烧合成及TiAl与钛的同步连接.采用SEM和XRD分析了界面的微观组织、断口形貌和相组成,采用三点弯曲试验测试了连接接头的抗弯强度,并通过ANSYS有限元模拟分析了连接接头的残余应力及应变等力学特性.结果表明,在试验条件下,钛铝粉体反应充分,钛铝与钛的连接界面结合良好,连接界面结构为TiAl/Ti3Al/Ti(ss.Al)/Ti的层状梯度结构.接头最大抗弯强度346 MPa,断裂于TiAl-Ti3Al连接界面处,断裂形态表现为脆性断裂.试件最大残余应力位于TiAl-Ti3Al连接处,使该部位成为材料的薄弱环节.

Ti /TiAl gradient materials were prepared by field-activated pressure-assisted synthesis(FAPAS) process.The microstructure,phase composition and fracture morphography of the interface were analyzed by SEM and XRD.The bending strength of the sample was tested by three-point bending test.Meanwhile,finite element analysis with ANSYS code was used to calculate the mechanical properties such as residual stress and deformation.It was shown that fine TiAl particles were formed with FAPAS and maximum bending strength as high as 346 MPa was obtained in the Ti/TiAl interface.The interface were layered gradient structure of TiAl/Ti3Al/Ti(ss.Al)/Ti.The fracture located in the TiAl-Ti3Al interface,and showed brittle fracture morphology.The maximum residual stress sited in the TiAl-Ti3Al interface,which was the position of weakness of the material.