FRACTURE BEHAVIOUR OF TiAi AND EFFECTS OF ITS MICROSTRUCTURE AND HYDRIDES
GAO Kewei; WANG Yanbin; CHU Wuyang; XIAO Jimei (University of Science and Technology Beijing)
Cite this article:
GAO Kewei; WANG Yanbin; CHU Wuyang; XIAO Jimei (University of Science and Technology Beijing). FRACTURE BEHAVIOUR OF TiAi AND EFFECTS OF ITS MICROSTRUCTURE AND HYDRIDES. Acta Metall Sin, 1992, 28(7): 30-35.
Abstract Effects of microstructure and hydrides contained on yield strength, σ_(ys), critical fracture strength, σ_F, and fracture toughness, K_(Ic), of TiAI alloy have been studied. Results show that σ_(ys) and σ_F increase slightly with size reduction of equiaxial grains of single phase γ. Yet σ_(ys), σ_F and K_(Ic) increase substantially if lamellar structure of bi-phase γ+α_2 occurred. Hydride may cause the increase of σ_(ys) and the decrease of K_(Ic). The suscepitibility for lamellar structure to hydrogen embrittlement may be lower than that for the equiaxial single phase γ. Resistance to cleavage-like crack initiation in TiAl alloy increases gradually with as steady-state propagation of crack. When plastic zone at crack tip and deformation developed up to critical value, the cleavage-like cracks initiate along slip band in plastic zone.
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