摘要
通过拉伸测试和显微分析方法研究搅拌摩擦焊Al-5.50Mg-0.45Mn和Al-5.50Mg-0.45Mn-0.25Sc-0.10Zr(质量分数,%)合金的显微组织和力学性能。结果表明,Al-Mg-Mn接头的屈服强度、抗拉强度和伸长率分别为(191±3)MPa、(315±1)MPa和(4.8±1.9)%,Al-Mg-Mn-Sc-Zr接头的分别为(288±5)MPa、(391±2)MPa和(3.4±1.0)%。相比Al-Mg-Mn接头,Al-Mg-Mn-Sc-Zr接头晶粒更细小、平均取向差角更低、小角度晶界百分数更高。两种接头的断裂位置均位于焊核区(WNZ),在该“最薄弱微区”内,Al_(3)(Sc_(1-x)Zr_(x))纳米粒子的平均尺寸为(9.92±2.69)nm,可提供有效奥罗万和晶界强化,使Al-Mg-Mn接头的屈服强度提高97 MPa。
Microstructure and mechanical properties of friction-stir-welded Al-5.50Mg-0.45Mn and Al-5.50Mg-0.45Mn-0.25Sc-0.10Zr(wt.%)alloys were investigated by tensile tests and microscopy methods.The results show that the yield strength,ultimate tensile strength and elongation of the Al-Mg-Mn joint are(191±3)MPa,(315±1)MPa and(4.8±1.9)%,respectively.The corresponding values of the Al-Mg-Mn-Sc-Zr joint are(288±5)MPa,(391±2)MPa and(3.4±1.0)%.The Al-Mg-Mn-Sc-Zr joint has smaller grain size,lower average misorientation angle and higher low-angle grain boundary fraction than the Al-Mg-Mn joint.Both the two joints fracture at the weld nugget zone(WNZ),and Al_(3)(Sc_(1-x)Zr_(x))nano-particles with a mean size of(9.92±2.69)nm still remain in this“weakest zone”.Theoretical calculation indicates that nano-particles can provide Orowan and grain boundary strengthening in WNZ,increasing the yield strength of the Al-Mg-Mn joint by 97 MPa.
作者
朱鑫文
邓英
赖毅
郭一帆
杨子昂
傅乐
徐国富
黄继武
Xin-wen ZHU;Ying DENG;Yi LAI;Yi-fan GUO;Zi-ang YANG;Le FU;Guo-fu XU;Ji-wu HUANG(School of Materials Science and Engineering,Central South University,Changsha 410083,China;State Key Laboratory of Power Metallurgy,Central South University,Changsha 410083,China;Applied Materials Science,Department of Engineering Science,Uppsala University,Uppsala 75121,Sweden)
基金
financially supported by the Natural Science Foundation of Hunan Province,China(Nos.2020JJ4114,2016JJ3151)
the National Natural Science Foundation of China(No.51601229)
the Young Elite Scientist Sponsorship Program by CAST,China(No.2015QNRC001)
the Hunan Province Innovation Platform and Talent Plan,China(No.2015RS4001)
the Open-End Fund for the Valuable and Precision Instruments of Central South University,China(No.CSUZC201815)。
关键词
铝合金
强度
搅拌摩擦焊
纳米粒子
显微组织
aluminum alloy
strength
friction stir welding
nano-particle
microstructure
