高應(yīng)變速率下Mg-3Zn-1Y鎂合金的各向異性及變形機(jī)制

高應(yīng)變速率下Mg-3Zn-1Y鎂合金的各向異性及變形機(jī)制Anisotropy and deformation mechanisms of as-extruded Mg-3Zn-1Y magnesium alloy under high strain rates

采用分離式霍普金森壓桿裝置，研究了擠壓態(tài)Mg-3Zn-1Y鎂合金高速?zèng)_擊變形下的動(dòng)態(tài)力學(xué)行為及各向異性。從微觀變形機(jī)制的角度探討了具有強(qiáng)烈初始基面織構(gòu)的擠壓態(tài)鎂合金產(chǎn)生各向異性的原因。分析結(jié)果表明：在高速變形條件下，由于加載方向不同擠壓態(tài)Mg-3Zn-1Y鎂合金的壓縮行為表現(xiàn)出一定的各向異性。擠壓態(tài)Mg-3Zn-1Y鎂合金宏觀上的各向異性是由于不同的微觀變形機(jī)制所引起的，沿?cái)D壓方向壓縮時(shí)，當(dāng)應(yīng)變量較小時(shí)變形機(jī)制主要為拉伸孿晶，當(dāng)應(yīng)變量增加時(shí)會(huì)有柱面滑移參與變形，當(dāng)應(yīng)變量達(dá)到一定值時(shí)滑移成為其主要的變形方式。而沿?cái)D壓橫向壓縮時(shí)，隨著應(yīng)變速率增加變形方式由壓縮孿生為主變?yōu)榛婊坪椭婊埔约岸五F面滑移等多種滑移方式協(xié)同變形。

The dynamic deformation behavior and anisotropy of an as-extruded Mg-3Zn-1Y magnesium alloy under high strain rates were investigated by split Hopkison pressure bar (SHPB).The reasons for the anisotropy were analyzed in terms of deformation mechanisms. The results demonstrate that as-extruded Mg-3Zn-1Y magnesium alloy exhibits pronounced anisotropy in compression according to the loading direction. The anisotropy of the as-extruded Mg-3Zn-1Y magnesium alloy are arised from the variety of the deformation mechanisms. When the loading direction was along extrusion direction,the predominant deformation mode changes from extension twinning at a lower strain to prismatic slip at a higher strain.While compressed along ERD,the predominant deformation mode changes from contraction twinning to a coordination of basal,prismatic and second order pyramidal slip with the increasing of strain.

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