Formation of Gradient Micro-Porous Titanium-Aluminides Through Elemental Powder Metallurgy

摘要

The research into alloys, specifically titanium and aluminum alloys (Ti & Al), has rapidly growing technological importance. The combined research into Ti-Al alloys in the field of powder metallurgy has advanced the fabrication of a part with high compressive strength, low relative density and material properties in addition to being a cost-effective process. In this work Ti-Al alloys were created using elemental Ti and Al powders. Elemental powders with a melting point of over 1000°C were sintered via liquid phase sintering (LPS). LPS is a process used for forming high performance, multiple-phase components from powders. It involves sintering at a temperature between the melting points of the two powders. The structural morphology, pore size and location were evaluated using Scanning Electron Microscopy (SEM) and optical microscopy. These methods allowed visible evidence of structural anomalies providing a capillary action which pulled the liquid Al to the surface and resulted into a densification of the part at the surfaces. The dense structure was seen on both the top and bottom of the samples with a layer of predominantly Al. The average on the top surface layer using optical measurements was 0.48mm and the bottom was 0.97mm.