Effect of 800℃ Thermal Exposure on the Microstructure and Properties of Ultrafine-grained Cr-77.5Nb Alloy

The micro-nanocrystalline Laves phase NbCr₂/Nb composite materials were prepared by mechanical alloying and hot pressing.The composites were exposured at 800℃ in vacuum for 10h、30h and 50h and the effects of the thermal exposure time on the microstructure and the room temperature mechanical properties of the composites were investigated.The results indicate that with the increase of the exposure time, the alloy has the higher relative density and strain, but Vickers hardness, yield strength and compressive strength increased in the early time, and then decreased later.