Effect of microstructure on fatigue crack propagation behavior of diffusion-bonded titanium alloy laminates
TA2/TA2/TA2 laminates were fabricated by diffusion bonding technology.Through introducing Ti55 heterogeneous layer,TA2/Ti55/TA2 heterogeneous laminates were fabricated.The fatigue life of two kinds of laminates was compared by fatigue crack propaga-tion test,and the influence of heterogeneous layer on fatigue crack propagation behavior of laminates was studied.The influence mecha-nism of heterogeneous layer on fatigue crack propagation behavior of laminates was investigated by SEM and EBSD microscopic observa-tions.The fatigue crack propagation life of heterogeneous laminate is 1.65 times of that of homogeneous laminate.Fatigue crack propaga-tion rate decreases by 53.1％when the crack tip approaches TA2/Ti55 interface from TA2.The slow down of fatigue crack propagation rate results from the increase of interface obstacles,the decrease of plastic zone size of fatigue crack tip and lower preferred grain orientation.
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