Improving tensile properties of dilute Mg-0.27Al-0.13Ca-0.21Mn (at.%) alloy by low temperature high speed extrusion
Improving tensile properties of dilute Mg-0.27Al-0.13Ca-0.21Mn (at.%) alloy by low temperature high speed extrusion
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DOI：
10.1016/j.jallcom.2015.07.051
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发表时间：
2015-11
影响因子：
6.2
通讯作者：
T. Nakata;T. Mezaki;Chao Xu;K. Oh-ishi;K. Shimizu;Satoru Hanaki;S. Kamado
中科院分区：
文献类型：
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作者：
T. Nakata;T. Mezaki;Chao Xu;K. Oh-ishi;K. Shimizu;Satoru Hanaki;S. Kamado
铸态Mg-0.27Al-0.13Ca-0.21Mn（at.%）合金在350 °C至500 °C的温度下挤出。研究了不同挤压温度下挤压过程中合金组织的变化，以阐明挤压过程中的动态再结晶机制，并研究了挤压温度对合金组织和力学性能的影响。在350 °C至500 °C的宽温度范围内，即使当铸态稀Mg-0.27Al-0.13Ca-0.21Mn（at.%）合金被用作用于挤压的坯料。低温挤压由于发生了连续动态再结晶（CDRX）和双孪晶，细化了晶粒，弱化了基面织构。结果，在350 °C下挤压的合金样品即使在挤压态条件下也表现出比T5处理的6063铝合金和商业AZ 31镁合金更高的206 MPa的拉伸极限应力和更高的29%的拉伸延展性。此外，Hall-Petch系数的压缩弹限应力是1.8倍大的拉伸之一，导致屈服应力的各向异性（压缩弹限应力/拉伸屈服应力比）的改善。
As-cast Mg-0.27Al-0.13Ca-0.21Mn (at.%) alloy was extruded at temperatures from 350 °C to 500 °C. We examined the microstructural changes during extrusion at different temperatures to clarify dynamic recrystallization mechanisms during extrusion, and also investigated the effect of extrusion temperature on microstructures and mechanical properties of the alloy. High extrusion exit speed of 60 m/min was successfully achieved at wide range of temperatures from 350 °C to 500 °C even when as-cast dilute Mg-0.27Al-0.13Ca-0.21Mn (at.%) alloy was used as a billet for the extrusion. The extrusion at low temperature refines grain size and weakens basal texture due to continuous dynamic recrystallization (CDRX) together with double twinning. As a result, the alloy sample extruded at 350 °C exhibits higher tensile proof stress of 206 MPa and higher tensile ductility of 29% than T5-treated 6063 aluminum alloy and commercial AZ31 magnesium alloy even in an as-extruded condition. Furthermore, Hall–Petch coefficient for compressive proof stress is 1.8 times larger than that for tensile one, resulting in improvement of yield stress anisotropy (compressive proof stress/tensile yield stress ratio).