DENSIFICATION AND MICROSTRUCTURAL CONTROL OF NEAR GAMMA-TiAl INTERMETALLIC POWDERS BY HIPING

Authors
  1. Wallace, W.
  2. Zhao, L.
  3. Beddoes, J.C.
  4. Morphy, D.
Corporate Authors
Institute for Aerospace Research, Ottawa ONT (CAN);Carleton Univ, Ottawa ONT (CAN) Dept of Mechanical and Aerospace Engineering;Chief of Research and Development, Ottawa ONT (CAN) Director Research and Development Air
Abstract
Hot isostatic pressing has been used to consolidate pre-alloyed powders of near gamma-titanium aluminide with attention being paid to the effects of HIP parameters on densification, microstructural control and properties. Three alloys have been studied, namely Ti-48A1, Ti-48A1-2W, and Ti-47.5A1-3Cr. (atom %). The W containing alloy required a temperature of 1100C to eliminate proposity, but full density was achieved at lower temperatures for the other two alloys. While the consolidated Cr powder possessed a uniform microstructure, the other two alloys retained a dendritic structure even when HIP'ed at 1250C. HIP cycles with varying temperatures and pressures were therefore designed to refine and homogenize the microstructures. The densities and microstructures resulting from the modified HIP cycles were characerized and compared to those obtained at constant temperatures and pressures. Methods of optimizing the HIP parameters to produce a homogenous microstructure suitable for further thermo-mechanical processing (TMP) or service application are discussed.
Keywords
HIP - HOT ISOSTATIC PRESSING
Date of publication
30 Apr 1993
Number of Pages
10
DSTKIM No
94-03033
CANDIS No
129481
Format(s):
Hardcopy;Originator's fiche received by DSIS

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