高温退火对铸轧Ti/Al复合板界面组织与性能的影响

Effect of high temperature on interfacial microstructure and properties of Ti/Al composite plate

采用SEM、EBSD、XRD、微观硬度、室温拉伸实验、T型剥离实验等手段研究高温退火对铸轧Ti/Al复合板界面微观组织与力学性能的影响。结果表明:高温退火(550℃)过程中,Ti基体的微观组织几乎不发生变化,Al基体在退火1 h时全部发生再结晶并开始长大;退火过程中,界面处的扩散层逐渐变厚,并在15 min时生成第二相TiAl_(3),在1 h时第二相TiAl_(3)连接成片,Ti/Al复合板界面的结合强度迅速下降。退火30 min时,铸轧Ti/Al复合板界面的结合强度达到最大值,约为23.6 N/mm;退火1 h时,铸轧Ti/Al复合板的抗拉强度和伸长率达到峰值,分别为236 MPa和27.6%,均高于铸轧态。

The effects of high temperature annealing on the interface microstructure and mechanical properties of cast-rolled Ti/Al composite plates were investigated by means of SEM,EBSD,XRD,microhardness,tensile test at room temperature and T-shaped peeling test,etc.The results show that the microstructure of Ti matrix hardly changes during annealing at 550℃,while the Al matrix recrystallizes and begins to grow after annealing for 1 h.During the annealing process,the diffusion layer at the interface gradually thickens,and the second phase TiAl_(3)is generated at 15 min,and the second phase TiAl_(3)is connected into flakes at 1 h,and the bonding strength of the Ti/Al composite plate interface is decreased rapidly.The bonding strength of Ti/Al composite plate reaches the maximum value of 23.6 N/mm after annealing for 30 min.At 1 h annealing,the tensile strength and elongation of the cast-rolled Ti/Al composite plate reach the peak values of 236 MPa and 27.6%,respectively,which are higher than those of the cast-rolled Ti/Al composite plate.