【作者】 李成杰； 漆燕； 白贵超； 崔奇； 孙宏飞； 房文斌；

【Author】 Li Cheng-jie;Qi Yan;Bai Gui-chao;Cui Qi;Sun Hong-fei;Fang Wen-bin;Institute of Materials, China Academy of Engineering Physics;School of Materials Science and Engineering, Harbin Institute of Technology;

【机构】 中国工程物理研究院材料研究所； 哈尔滨工业大学材料科学与工程学院；

【摘要】 本文以铸态商业纯镁作为初始材料,采用两道次累计大比率挤压工艺对其进行加工,最终得到直径为5mm的细晶纯镁棒材。利用光学显微镜和力学性能测试分别对挤压过程中纯镁的组织演变、力学性能以及加工硬化行为进行研究。研究结果表明,经过两道次挤压以后,纯镁的晶粒尺寸由几百微米减小到6μm以下,最小可以达到3.56μm;屈服强度和抗拉强度分别由23.7MPa和82.1MPa提高到170MPa和200MPa;延伸率由4.6%提高到19%以上。强度的提高主要得益于晶粒尺寸的细化和基面织构强化;塑性的提高主要源自于晶粒细化以后,非基面滑移和晶界滑移起到了重要协调作用。更多还原

【Abstract】 Pure magnesium were processed by two-pass cumulative high ratio extrusion with as-cast Mg as the original material and then the as-extruded pure Mg bars with 5 mm in diameter were obtained. The microstructure evolution, mechanical properties and work hardening behavior of pure Mg were investigated by optical microscopy and mechanical properties test, respectively. The results show that the grain size is obviously reduced from several hundred micrometers to below 6μm and the smallest average grain size is 3.56μm after two passes extrusion. The yield strength, and ultimate tensile strength of pure Mg were improved from 23.7 MPa and 82.1 MPa to 170 MPa and 200 MPa, respectively. The elongation was enhanced from 4.6% to over 19%. The increase of strength mainly results from grain size refinement and basal texture strengthening. The non-basal slip systems and grain-boundary slipping can be easily activated in fine grained pure Mg, which is favorable to the increase of elongation.更多还原