In situ neutron diffraction studies on the elevated-temperature deformation behavior of a TiAl–W alloy

The evolution of elastic lattice strain in a Ti–48Al–2W (at.%) alloy, subjected to (1) quasistatic tensile loading and (2) constant-load tensile creep, was investigated at 1033K using in situ neutron diffraction. During the quasistatic test to a maximum stress of 435MPa, a- and c-axes lattice strains increased linearly with a small degree of anisotropy (E¯a∕E¯c≅0.9) up to 200MPa, followed by a significant redistribution of load above 260MPa due to the plastic anisotropy. Time-resolved in situ measurements were also performed during the creep at 276 and 327MPa. The results show that lattice strain evolution during the primary creep is qualitatively similar to the quasistatic case under the current test conditions.