Study on Sintering Behavior, Microstructure and Property of trace yttrium enhanced fine -grained W alloy

Abstract:

Through the ordinary moulding - presintering, sintering at 1800-1950 ℃,the fine-grained tungsten alloys were fabricated with ultrafine/nano composite powders of W-0.3%Y which were prepared by Sol-spray drying- Nano in situ composite.The microhardness and tensile strength of alloys were detected,Moreover ,Scanning electron microscopy (SEM) and energy dispersive X-ray spectroscopy were used to examine fracture morphology and microstructure .The evolution of Sintering and Fracture behavior were investigated.The results show that the added trace yttrium exists in the form of Y₂O₃ as the second phase particles dispersing throughout grain boundary and inner grain of W, restraining tungsten grain growth and making the grains to be significantly refined,which is to improve the mechanical properties of the alloys.Besides,The fracture mode of tungsten alloy with adding trace yttrium was changed from intergranular fracture transition of pure tungsten to mainly intergranular fracture and part transgranular fracture.