不同挤压速率的AZ31镁合金背压式等通道角挤压变形模拟  

Simulation of Back-pressure Equal-channel Angular Pressing Deformation of AZ31 Magnesium Alloy with Different Extrusion Rates

作　　者：孙兆丹 魏爱玲 张乐 刘一笑 SUN Zhaodan;WEI Ailing;ZHANG Le;LIU Yixiao(Langfang Yanjing Vocational Technical College,Langfang 065200,China;College of Materials Science and Engineering,Hebei University of Science and Technology,Shijiazhuang 050018,China)

机构地区：[1]廊坊燕京职业技术学院,河北廊坊065200 [2]河北科技大学材料科学与工程学院,河北石家庄050018

出　　处：《热加工工艺》2024年第11期150-154,共5页Hot Working Technology

基　　金：河北省自然科学基金重点资助项目(E2018203339)。

摘　　要：晶粒细化是改善镁合金材料强韧性的关键手段之一,而剧烈塑性变形工艺常作为细化晶粒的首选技术。等通道角挤压工艺(Equal Channel Angular Pressing,ECAP)由于可极大地细化晶粒而被广泛应用,然而一般的ECAP工艺在细化晶粒到一定程度后便难以继续,亟需对其改进。针对此,设计一种新型背压式ECAP工艺,采用Deform 3D软件对该工艺进行模拟,研究了不同挤压速率对AZ31镁合金变形过程的影响。结果表明,在等通道角挤压过程中设置背压可促进等效应变,且对应变速度非常敏感。在低挤压速率下其局部金属流动、等效应力明显加剧,在达到一定程度后,背压对释放应力集中效果明显,局部应力及应变增大不明显。这主要与镁合金变形机制基面滑移及棱柱面非基面滑移有关。此种新工艺对于镁合金材料进一步晶粒细化和提高性能有重要作用。Grain refinement is one of the key technologies to improve the strength and ductility of Mg alloys.The severe plastic deformation is often used as the preferred technique for grain refinement.The equal channel angular pressing(ECAP)is widely used because it can greatly refine the grains.However,the general ECAP process is difficult for further refining grains when the grains are refined to a certain extent,and it needs to be improved.Thus,a new type of back pressure equal channel angular pressing process was designed,and the process was simulated by using Deform 3D software,and the effects of different extrusion rates on the deformation process of AZ31 magnesium alloy were studied.The results show that setting back pressure in the process of equal channel angular extrusion can promote the equivalent strain,which is very sensitive to the strain rate.At low extrusion rate,the local metal flow and equivalent stress are significantly intensified.After reaching a certain level,the effect of back pressure on releasing stress concentration is obvious,and the local stress and strain increase is not obvious.This is mainly related to the deformation mechanism of magnesium alloy basal plane and prismatic non-basal slip.This new process plays an important role in further grain refinement and performance improvement of magnesium alloy materials.

关 键 词：镁合金 背压 等通道角挤压 

分 类 号：TG379[金属学及工艺—金属压力加工]