The influence of magnetron sputtered silver and titanium coatings on the compaction and properties of surface modified PM Ti-48Al powders

摘要

Thin layers of silver and titanium were deposited onto commercial Ti-Al-48 particles by magnetron sputtering prior to their consolidation by hot isostatic pressing and subsequent heat treatment. Based on picnometry and electron probe microanalysis results, average values of 1.5 and 2.5 at.%, respectively, were obtained for the silver and titanium contents in the coated particles. The surface modified Ti-Al-48 particles exhibited improved sintering ability than the unmodified ones. The consolidated samples have duplex microstructures formed by gamma-TiAl and gamma-TiAl 1 + alpha(2)-Ti3Al grains. Ag-rich nanoprecipitates were detected in the microstructure of the compacted Ti-Al-48 + Ag. sample. The coatings are no longer visible at the grains boundaries after a subsequent homogenization heat treatment at 1200 degrees C. The highest values of hardness and Young's modulus were obtained for the Ti-Al-48 + Ag sample, associated with a higher density and a lower percentage of pores.