Hot isostatic pressing of Chevrel phase bulk and hydrostatically extruded wire samples

Abstract

Abutmct--In order to lower final siiiteriiig temperatures for Chevrel phase ( C P ) wires, we have iiivestigated low-temperature hot isostatic pressing (HIP'ing) of both bulk and wire samples. We have fabricated (Pb,Sn)-based Chevrel phase (CP) monofilament and 61 filament wires by hydrostatic extrusioii of (Cu or Cu-Ni)/(Nb or V ) / C P composites, followed by cold drawing. We have investigated the CP/barrier reaction during heat treatment. fiiidiiig V is unsuitable. but N h is suitable a t these lower teiiiperatures for prereacted Pbl Sii,Mo6 Sa cores. We prepared powders of the biliary Chevrel phase Moas8 by acid leaching of Li,Mo,Sa aiid Ni,MoeS8. We prepared bulk samples of PbMocSR aiid Pbl-,Sii,MocSg by HIP'iiig mixtures of '*Pb+MocSs" powders ( z i i 4 z f u route) or by prereactiiig Pb, Sn aiid Moss8 powders before HIP'iiig (prereacted route). The zn sztu powders were HIP'ed uiider different time-t~inperature-pressure coiidi tioiis up to 1 2 h/GOO "C/200 MPa, producing partially consolidated PbMoeS8 samples. Further HIP'iiig of all saiiiples at temperatures of 700, 800 and 1000 OC, 200 MPa pressure and tiiiies of 8 aiid 80 hours produced additional consolidation, up to 95% of full density. As the aggressiyeiiess (temperature and time iiiider pressure) of the H I P process increased, the density, hardness, critical temperature, aiid inagnetization critical current deiisi ty increased.