A high-strength, ductile Al-0.35Sc-0.2Zr alloy with good electrical conductivity strengthened by coherent nanosized-precipitates
A high-strength, ductile Al-0.35Sc-0.2Zr alloy with good electrical conductivity strengthened by coherent nanosized-precipitates
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DOI：
10.1016/j.jmst.2017.01.017
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发表时间：
2017-05
影响因子：
10.9
通讯作者：
R. Guan;Yongfeng Shen;Zhanyong Zhao;Xiang-Jie Wang
中科院分区：
文献类型：
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作者：
R. Guan;Yongfeng Shen;Zhanyong Zhao;Xiang-Jie Wang
金属材料的延展性和导电性与其强度呈负相关，导致难以同时优化所有三者。我们设计了一种Al-Sc-Zr基合金，采用半固态挤压，产生良好的强度和延展性之间的平衡，沿着具有优异的导电性。直径为3 mm的Al-0.35Sc-0.2Zr丝材具有最佳的综合性能：抗拉强度为210 ± 2 MPa，延伸率为7.6% ± 0.5%，电导率为34.9 ± 0.05MS/m。在380 °C下，随着时效时间从1 h增加到96 h，纳米Al 3（Sc，Zr）析出相的平均粒径从6.5 ± 0.5 nm增加到25.0 ± 0.5 nm，相应的体积分数从（6.2 ± 0.1）× 10− 4增加到（3.7 ± 0.1）× 10−3。通过透射电子显微镜观察证明，高强度源于大量纳米级Al 3（Sc，Zr）沉淀物对位错运动的有效阻挡，同时由于具有极低电阻率的共格沉淀物，导电性和延展性保持在高水平。
Ductility and electrical conductivity of metallic materials are inversely correlated with their strength, resulting in a difficulty of optimizing all three simultaneously. We design an Al-Sc-Zr-based alloy using semisolid extrusion to yield a good trade-off between strength and ductility along with excellent electrical conductivity. The Al-0.35Sc-0.2Zr wire with a diameter of 3 mm exhibited the best combined properties: a tensile strength of 210 ± 2 MPa, elongation of 7.6% ± 0.5%, and an electrical conductivity of 34.9 ± 0.05 MS/m. The average particle size of nanosized Al3(Sc, Zr) precipitates increased from 6.5 ± 0.5 nm to 25.0 ± 0.5 nm as the aging time increased from 1 h to 96 h at 380 °C, accompanied by the corresponding volume fraction variation from (6.2 ± 0.1) × 10−4to (3.7 ± 0.1) × 10−3. As proved by transmission electron microscopy observation, the high strength originates from the effective blockage of dislocation motion by numerous nanosized Al3(Sc, Zr) precipitates whilst both electrical conductivity and ductility remain at a high level due to the coherent precipitates possessing an extremely low electrical resistivity.