CAJ | 학술논문

镁合金的各向异性是南滑移和孪生共同作用产生,而产生是协调镁合金塑性变形的重要机制.尤其在低温变形条件下,滑移和孪生相互协调并影响其成形性能.为准确描述镁合金成形过程的变形机制,文章建立了一种基于滑移和孪生相互耦合的多晶体塑性模型,并引入到有限元分析过程中.其中金属塑性流动,由每个晶粒内滑移面上沿滑移方向产生的剪切变形及孪生面上的孪生变形共同组成,进而采用率无关晶体塑性模型模拟了AZ31镁合金压缩过程,并给出了孪晶体积分数随时间的变化曲线.研究表明,孪晶体积分数随变形应力产生相应变化,并且基面滑移和孪生是影响镁合金窒温成形件能及加工硬化的主要因素.
미합금적각향이성시남활이화련생공동작용산생,이산생시협조미합금소성변형적중요궤제.우기재저온변형조건하,활이화련생상호협조병영향기성형성능.위준학묘술미합금성형과정적변형궤제,문장건립료일충기우활이화련생상호우합적다정체소성모형,병인입도유한원분석과정중.기중금속소성류동,유매개정립내활이면상연활이방향산생적전절변형급련생면상적련생변형공동조성,진이채용솔무관정체소성모형모의료AZ31미합금압축과정,병급출료련정체적분수수시간적변화곡선.연구표명,련정체적분수수변형응력산생상응변화,병차기면활이화련생시영향미합금질온성형건능급가공경화적주요인소.
The plastic anisotropy of HCP metal is usually caused by preferred orientation of grains, which are developed by the combination role of the slip and twinning deformation at room temperature. Consideration of plastic anisotropy is essential in accurate simulations of metal forming processes. A new constitutive model for polycrystalline plastic deformation by slip and twinning combination has been formulated, and then introduced into a finite element program. Metal flow is assumed to occur by crystallographic slip on given slip and twinning systems within each crystal. Then compressed Mg alloy is studied using a rate independent polycrystalline plasticity finite element analysis. The ear distributions of polycrystalline are computed for different typical initial orientation cases. The values of the twinning factors associated with slip system deformation have deduced. It is been found that the twinning factors are various with the value of the stress. The basal slip and twinning system play the dominant role in the deformation of magnesium which may for the most part be attributed to the strain harden.