Modeling of grain-boundary effects and intergranular and transgranular failure in polycrystalline intermetallics

被引:3
作者
Kameda, T. [1 ]
Zikry, M. A.
Rajendran, A. M.
机构
[1] Univ Tsukuba, Inst Engn Mech & Syst, Tsukuba, Ibaraki 3058573, Japan
[2] N Carolina State Univ, Dept Mech & Aerosp Engn, Raleigh, NC 27695 USA
[3] Army Res Off, Res Triangle Pk, NC USA
来源
METALLURGICAL AND MATERIALS TRANSACTIONS A-PHYSICAL METALLURGY AND MATERIALS SCIENCE | 2006年 / 37A卷 / 07期
关键词
D O I
10.1007/BF02586131
中图分类号
T [工业技术];
学科分类号
08 ;
摘要
A three-dimensional multiple-slip dislocation-density-based crystalline formulation and specialized finite-element formulation were used to investigate dislocation-density transmission and blockage in nickel-aluminide polycrystalline aggregates, which were subjected to dynamic loading conditions, with a macroscopic crack and different distributions of random low-angle and coincident site lattice (CSL) grain boundaries (GBs). An interfacial GB scheme was developed to determine whether dislocation-density pileups or transmissions occur as immobile and mobile dislocation densities evolve along different slip systems. The three-dimensional dislocation-density-based crystalline formulation is based on inter-related mechanisms that can occur due to the generation, trapping, interaction, and annihilation of mobile and immobile dislocation densities that are generally associated with large strain-high-strain-rate plasticity in L1(2)-ordered intermetallics. A crack-tip shielding factor was also formulated to delineate between transgranular and intergranular crack growth. The current results indicate that aggregates with a high frequency of Sigma 33a GBs would be susceptible to blunted transgranular crack growth due to high dislocation-density transmission rates and shear-stress accumulations, and that an aggregate with a high frequency of Sigma 17b GBs would be susceptible to sharp intergranular growth due to a large number of dislocation-density pileups and an accumulation of large normal stresses ahead of the crack tip.
引用
收藏
页码:2107 / 2115
页数:9
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