Elevated temperature tensile behavior and microstructure evolution of liquid phase sintered 90W–7Ni–3Fe alloy

The tensile mechanical properties and fracture behavior of 90W–7Ni–3Fe alloy have been investigated in the temperature range from 298 K to 1473 K. The results showed that the mechanical properties of the alloy were highly sensitive to temperature and decreased with increasing temperature in most cases. The maximum Rockwell hardness and higher ultimate tensile strength at 673 K explicated better work hardening ability. In addition, it was most likely that W grains refinement resulted in a significant increase of Vickers micro hardness at 1073–1473 K. Scanning Electron Microscopy (SEM) was used to observe the tensile fracture morphology. It was found that the fracture mechanisms of the alloy gradually evolved from a mixture of W cleavage fracture and matrix phase dimples at room temperature to a mixture of the interface separation of W/W particles and W/matrix at higher temperature. Additionally, when the temperature rose to 1473 K, the phenomenon of coarse matrix occurred. Suspiciously, the deteriorating mechanical properties at elevated temperatures was caused by the influence of the precipitation phase.