Abstract
In-situ TiB2/AZ80 composite was prepared by a simple casting method, and then hot-rolling. Effects of TiB2 reinforcements on the microstructural evolution of composite were investigated. In-situ TiB2 particles could refine the as-cast grains of AZ80 alloy, and promote recrystallization through particle stimulated nucleation (PSN) effect. Due to the grain refinement and the PSN effect of TiB2, the twin induced recrystallization mode in AZ80 alloy is transformed into grain boundary and particle dominated recrystallization process in the TiB2/AZ80 composite, which suppresses the generation of coarse shear bands during rolling and improves the rolling ability. At the same time, the morphology of TiB2 particle clusters was continuously modified with the increase of rolling passes, and finally formed fiber-like distribution characteristics. Fine grain strengthening and thermal mismatch strengthening are the main strengthening mechanisms of the composite sheet. Internal toughening mechanisms are texture weakening, the proliferation of more<c+a>dislocations, higher Schmidt factor and more uniform strain distribution induced by the PSN effect. In addition, external toughening ones should attribute to bending and deflection of cracks resulting from fiber-like particle distribution characteristics. Thus, the strength and toughness of the TiB2/AZ80 composite were simultaneously enhanced.
Published Version
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