Effect of thermochemical processing with hydrogen on O phase formation in super-α_2 alloy

摘要

Since the discovery of O phase, an orthorhombic structure phase in I13AI based alloys, by Banerjee et al. [1], attention has been paid to the study of its formation in this type of alloy [2-4], especially when better tensile properties and fracture toughness, and creep resistance similar to that of a2 phase were found for alloys containing O phase [5-7], which provides a new possibility to enhance the mechanical properties of T^Al based alloys. On the other hand, in view of the room temperature brittleness shown by T13AI based alloys, much effort has also been devoted to improving the ductility of the alloys by modification of the microstructure, such as thermo-mechanical processing [8] and thermochemical processing (TCP) with hydrogen. Previous works [9-11] have shown that TCP with hydrogen can effectively modify the microstructure and improve the mechanical properties of the alloys. However, studies of the effect of TCP with hydrogen of the alloys on 0 phase formation in their microstructures have rarely been reported. The aim of the work reported here was to investigate the formation of 0 phase in the microstructure of super~a2 alloy, a Ti3Al based alloy, by TCP with hydrogenation in order to provide a basis for the application of this unique technique in this type of alloy.