Effects of sintering temperature and time on defect evolution and compression properties of Ti-Al3Ti laminated composites

For metal-intermetallic laminated composites,various types of defects often occur dur-ing the preparation process.This paper studied the evolution and formation mechanism of defects,such as pores,tunnel cracks,and delamination cracks in Ti-Al3Ti laminated composites prepared by vacuum hot-pressing method.Moreover,quasi-static and dynamic compression tests were per-formed to study the effects of pores and delamination cracks on the compression properties of the composites.The results showed that for Ti-Al3Ti laminated composites prepared at 710℃,their Al3Ti layers exhibit a porous structure,and the porosity of Al3Ti layers firstly decreases and then increases under the combined action of press,the self-propagating reaction and Al3Ti grain coars-ening.The tunnel cracks in Ti-Al3Ti laminated composites are resulted by tensile residual stresses and the inherent brittleness of Al3Ti.For Ti-Al3Ti laminated composites prepared at 680℃,the formation of delamination cracks is mainly related to the diffuse reaction of Ti/Al atoms and the Kirkendall effect,and the numbers of delamination cracks increase with the increasing of sintering time.Moreover,the pores and delamination cracks greatly deteriorate the compression properties of Ti-Al3Ti laminated composites.Crack-free and dense Ti-Al3Ti laminated composites exhibit the highest compression properties.