(沈陽工業(yè)大學(xué) 材料科學(xué)與工程學(xué)院，沈陽 110870)
摘 要: 為了研究鎂合金在高應(yīng)變速率下的動態(tài)變形行為及失效機制，采用分離式霍布金森壓桿(SHPB)裝置在室溫下對擠壓態(tài)Mg-Gd-Y鎂合金進行動態(tài)壓縮實驗，并利用金相和掃描電子顯微鏡對沖擊后的試樣進行顯微分析，探討了Mg-Gd-Y鎂合金沿擠壓方向(ED)、橫向(TD)及法向(ND)的動態(tài)壓縮力學(xué)性能和失效行為與塑性變形方式。結(jié)果表明：在動態(tài)壓縮載荷下，擠壓態(tài)Mg-Gd-Y鎂合金沿ED、TD、ND 3個方向表現(xiàn)出連續(xù)屈服的變形特征，隨應(yīng)變速率的提高，具有正應(yīng)變速率強化效應(yīng)，動態(tài)壓縮力學(xué)性能無明顯的各向異性，ED方向的動態(tài)壓縮性能略優(yōu)于其他兩個方向的；擠壓態(tài)Mg-Gd-Y鎂合金在動態(tài)壓縮載荷下的斷口形貌呈韌脆混合的準(zhǔn)解理斷裂特征，對載荷方向不敏感；擠壓態(tài)Mg-Gd-Y鎂合金在動態(tài)壓縮載荷下的變形方式為孿生和滑移共同作用機制，并伴隨動態(tài)再結(jié)晶現(xiàn)象。
關(guān)鍵字: Mg-Gd-Y鎂合金；分離式Hopkinson桿；動態(tài)力學(xué)性能；失效行為
（School of Materials Science and Engineering, Shenyang University of Technology, Shenyang 110870, China）
Abstract:In order to investigate the dynamic deformational behavior and failure mechanisms of magnesium under high strain rates, the split Hopkinson pressure bar (SHPB) was used to investigate the dynamic mechanical properties of extruded Mg-Gd-Y magnesium alloy at room temperature. The samples after compression were analyzed by scanning electron microscopy (SEM) and metallographic microscopy. The dynamic mechanical properties, crack performance and plastic deformation mechanism of extruded Mg-Gd-Y magnesium alloy along the extrusion direction (ED), transverse direction (TD) and normal direction (ND) were discussed. The results show that, the extruded Mg-Gd-Y magnesium alloy under dynamic compression along ED, TD and ND directions yields continuously, and has the positive strain rate effect when strain rates rise. The dynamic mechanical properties do not exhibit strong anisotropy and the dynamic compression properties along ED direction are the best among those of three directions. The fracture performance of extruded Mg-Gd-Y magnesium alloy along different directions is mix-fractured quasi-cleavage fracture and is not sensitive to the loading direction. The deformation mechanism of extruded Mg-Gd-Y magnesium alloy under high stain rate compression is a combination of twinning, slipping and dynamic recrystallization.
Key words: Mg-Gd-Y alloy; split Hopkinson pressure bar; dynamic mechanical property; failure behavior
