| Title |
Control of Porosity in an EPM - processed Ti-46.6Al-1.4Mn-2Mo Alloy |
| Authors |
김종균(Jong Kyun Kim) ; 황선근(Sun Keun Hwang) |
| Abstract |
Formation mechanism and control of pores in a gamma alloy synthesized by elemental powder metallurgy(EPM) was investigated. The chemical composition of the experimental alloy was Ti-46.6Al-1.4Mn-2Mo(at.%) and elemental powders were used as raw materials to synthesize the alloy by hot extrusion. Retained molybdenum was observed in as-extruded alloy, and formation of pores at molybdenum-rich regions was confirmed in heat treated alloy by back scattered electron imaging as well as by energy dispersive spectroscopy, The porosity increased with the average particle size of Mo powder. Depending on the processing condition the density of pores varied. Pores could not be easily detectable in as-extruded condition ; however, subsequent heat treatment brought them out. Pre-extrusion treatment affected the severity of porosity in extruded and heat-treated condition. Extended soaking or partial sintering prior to extrusion was found to be effective for suppressing porosity during the heat treatment to produce a fully lamellar structure. |