Mechanical Properties and Microstructure of TiB₂/Al Composite Prepared by Direct Reactive Method

The TiB2/Al composites were fabricated by direct reaction method at different initial reaction temperatures,and the remelting process was carried on.The microstructure and mehanical properties of composites were analyzed by means of OM,SEM and TEM.The reactive mechanism in the melt was also studied.The results show that the volume percent of TiB2 increased and its distribution improved as increase of initial reaction temperature.It seemed to be little effect on the distribution of TiB2 particles for the remelting treatment.The tensile strength and elongation were 181.2 MPa and 22.5% respectively for the composites remelted at 750 ℃ after fabricated at 850 ℃.In the process of TiB2/Al composite preparation,TiO2 and KBF4 in the mixed powder reacted with Al melt firstly.There might be mesophase AlB2 and TiAl3 appeared during the reaction.With the reaction progressing,AlB2 and TiAl3 with high free energy would decompose to TiB2 with lower free energy.