Near-Net-Shape Tungsten-Rhenium Alloy Parts Produced by Plasma Spray Forming and Hot Isostatic Pressing

摘要

Tungsten-5.0 mass% rhenium (W-5.0 mass%Re) composite feedstock was fabricated by a new cover method. Complex and thin-walled W-5.0mass%Re products (including one shaped charge liner and one throat) were produced by plasma spray forming (PSF) followed by hot isostatic pressing (HIPing). Scanning electron microscope (SEM), Archimedes method, Vickers hardness, tensile and compressive tests were employed to study microstructure, density, micro-hardness and mechanical properties of the parts. A lamellar structure consisting of vertical columnar grains, micron-sized pores and rough interlamellar contacts with gaps of sub-micron sizes between lamellae were found in PSF deposits. The relative density, micro-hardness, ultimate tensile strength (UTS) and compressive strength of PSF deposits were about 87 ± 1%, 321 ±4 HV_(0.025), 57 ±2 and 390 ±2 MPa, respectively. As dwell time of HIPing prolonging (from 2, to 4 and 6h), internal defects of PSF deposits including inter-lamellar gaps and micro-pores could be gradually mitigated or eliminated with initial lamellar structure transforming into granular one. Relative density and mechanical properties of W-Re alloys were gradually increased under the combined action of high temperature and pressure. Especially for W-Re deposits after 6h HIPing, the relative density, micro-hardness, UTS, compressive strength and yield stress were increased high up to 98 ± 1%, 490 ± 4HV_(0.025), 384 ± 2MPa, 1490 ± 2 and 879 ± 2 MPa, respectively. The mechanical properties and the ductility at room temperature of W-Re alloys were both higher than those of W deposits. 'Re effect' was revalidated and double checked in W-Re alloys fabricated by PSF and HIPing here.