Improvement Of Metallurgical Processing Parameters For EPM TiAl-1.4Mn-2Mo Alloy

초록

Laboratory alloy TiAl-1.4Mn-2Mo was synthesized by elemental powder metallurgy (EPM) and the tensile properties and the creep resistance were evaluated. The mechanical properties were comparable to or better than other gamma alloys made by ingot metallurgy. In the EPM processing of the laboratory alloy, it was important to select a fine Mo powder and to conduct a proper pre-extrusion treatment in order to ensure minimal porosity and uniform microstructure. Controlling the Mo powder size was necessary because of concerns on Kirkendall porosity and  phase formation. Pre-extrusion treatment was required to stabilize intermediate phases such as Ti2MoAl and TiAl3. Various post-extrusion heat treatments were devised to refine the final lamellar microstructure to a range of 30㎛ in packet size. Overall the present work supports the viability of the PM approach in developing gamma alloys.