Improvement of the Oxidation Resistance of EPM Gamma-TiAl Alloy by Y-Addition

초록

Improvement of the Oxidation Resistance of EPM Gamma-TiAl Alloy By Y-Addition. The oxidation resistance of gamma TiAl alloy was improved by Y-modification of the chemical composition. An elemental powder metallurgical method was used to consolidate a Ti46.6Al1.4Mn-2Mo alloys with Y additions varying in the amount of up to 0.6at.% Preparation procedure of the experimental materials consisted of blending of elemental powders, cold compacting, degassing and canning, and hot extrusion at 1250 temperature followed by heat treatments, The materials prepared in this way showed a tensile yield strength of up to 700Mpa and a tensile elongation of up to 3% at room temperature. From this result it was concluded that Y was beneficial in terms of the mechanical properties due to its role of imparting resistance to dislocation motions through solid solution hardening and precipitation hardening, and cocurrently scavenging harmful interstitial impurities. In consolidated and heat treated condition, Y2O3 particles formed internally, which reduced interstitial oxygen responsible for brittleness.