Liuyong He , Jiang Zheng , Mengning Xu , Tianjiao Li , Dongdi Yin , Bin Jiang , Fusheng Pan , Hao Zhou
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引用次数: 0
Abstract
Navigating the strength-ductility trade-off has been a persistent challenge in Mg alloys. Here, we address this issue through a novel multiple-direction pre-deformation at room temperature that introduces a high density of 〈c + a〉 dislocations into pure Mg via dislocation transmutation. This approach achieves a remarkable enhancement in the strength-ductility synergy, increasing the yield strength from 87.6 MPa to 156.6 MPa and improving elongation to failure from 7.7% to 17.6%. In general, introducing a high-density 〈c + a〉 dislocations in Mg alloys have been difficult due to the high CRSS at room temperature. Our findings reveal that extension twinning can act as a “dislocation converter,” transforming basal 〈a〉 dislocations in the matrix into 〈c + a〉 dislocations within twins. Intensive basal 〈a〉 dislocations were induced in pure Mg through pre-tension and subsequently transformed into 〈c + a〉 dislocations via extension twinning during compression. This process led to a substantial number of 〈c + a〉 dislocations and I1 stacking faults, contributing to the enhanced strength. The high density of 〈c + a〉 dislocations, combined with I1 stacking faults and a reduced c/a ratio within twins, enhances the activity of pyramidal 〈c + a〉 slip, thereby significantly improving ductility. This dislocation transmutation strategy offers a promising way for producing strength-ductility synergy in Mg alloys.
期刊介绍:
International Journal of Plasticity aims to present original research encompassing all facets of plastic deformation, damage, and fracture behavior in both isotropic and anisotropic solids. This includes exploring the thermodynamics of plasticity and fracture, continuum theory, and macroscopic as well as microscopic phenomena.
Topics of interest span the plastic behavior of single crystals and polycrystalline metals, ceramics, rocks, soils, composites, nanocrystalline and microelectronics materials, shape memory alloys, ferroelectric ceramics, thin films, and polymers. Additionally, the journal covers plasticity aspects of failure and fracture mechanics. Contributions involving significant experimental, numerical, or theoretical advancements that enhance the understanding of the plastic behavior of solids are particularly valued. Papers addressing the modeling of finite nonlinear elastic deformation, bearing similarities to the modeling of plastic deformation, are also welcomed.