Topic：A microstructure-based model for simulation of short fatigue crack growth in 3-D

Speaker: Prof. Tongguang Zhai (翟同广)

　　　　　Department of Chemical and Materials Engineering,
　　　　　University of Kentucky,
　　　　　Lexington, Kentucky 40506, USA

Time: 10:00-11:00, （Wed.) Jun.17 , 2015

Venue: Room 468, Lee Hsun Building, IMR CAS

A microstructure-based model for simulation of short fatigue crack growth in 3-D

Abstract: The talk will begin with a brief review on our recent research activities including: 1) anomalous strain rate effect on ductility in Mo-Re alloys; 2) formation mechanism of an unusual texture in Al alloys; 3) formation mechanism of the high-temperature precipitation in 6000 Al alloys; and 4) 3-D effects of microstructure on fatigue crack initiation in engineering alloys, etc. The talk will then be focused on a microstructure-based model that has recently been developed to quantify short fatigue crack growth in 3 dimensions in planar slip alloys, such as high strength Al alloys and Ni-base superalloys, etc. The model takes into account both the local driving force and resistance in calculating short crack growth. The resistance of a gran boundary to short fatigue crack growth was characterized to be as a Weibull-type function of the twist angle of the crack plane deflection at the boundary, using an experimental technique newly developed in the author’s lab. The total resistance at a grain boundary is also contributed by all its neighboring grain boundaries as a normal distribution function of distance. The driving force for crack growth is the ∆K at the furthest point along the crack. This model presents the potentials for more accurate prediction of the life of an engineering alloy and advancement of alloy design technology.