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

Abstract

Tungsten5.0 mass% rhenium (W5.0 mass%Re) composite feedstock was fabricated by a new cover method. Complex and thin-walled W5.0 mass%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 6 h), 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 WRe alloys were gradually increased under the combined action of high temperature and pressure. Especially for WRe deposits after 6 h HIPing, the relative density, micro-hardness, UTS, compressive strength and yield stress were increased high up to 98 « 1%, 490 « 4 HV 0.025 , 384 « 2 MPa, 1490 « 2 and 879 « 2 MPa, respectively. The mechanical properties and the ductility at room temperature of WRe alloys were both higher than those of W deposits. 'Re effect' was revalidated and double checked in WRe alloys fabricated by PSF and HIPing here.

Preparation, Mechanical Properties and Strengthening Mechanism of W-Re Alloys: A Review

“…The high-temperature strength of tungsten decreases with increasing the temperature [ 92 ]. The addition of Re scarcely improves the high-temperature strength of tungsten.…”