Sheared solid materials

Pramana

Akira Furukawa¹  Akira Onuki1¹  Akihiko Minami¹ 

[1] Department of Physics, Kyoto University, Kyoto 606-8502, Japan$$

关键词: Plastic flow;    dislocations;    free volume;    aging;    two-phase alloys;    incoherency.;   

DOI  :  

学科分类：物理（综合）

来源: Indian Academy of Sciences

【 摘 要 】

We present a time-dependent Ginzburg–Landau model of nonlinear elasticity in solid materials. We assume that the elastic energy density is a periodic function of the shear and tetragonal strains owing to the underlying lattice structure. With this new ingredient, solving the equations yields formation of dislocation dipoles or slips. In plastic flow high-density dislocations emerge at large strains to accumulate and grow into shear bands where the strains are localized. In addition to the elastic displacement, we also introduce the local free volume 𝑚. For very small 𝑚 the defect structures are metastable and long-lived where the dislocations are pinned by the Peierls potential barrier. However, if the shear modulus decreases with increasing 𝑚, accumulation of 𝑚 around dislocation cores eventually breaks the Peierls potential leading to slow relaxations in the stress and the free energy (aging). As another application of our scheme, we also study dislocation formation in two-phase alloys (coherency loss) under shear strains, where dislocations glide preferentially in the softer regions and are trapped at the interfaces.

【 授权许可】

Unknown