Al-6Mg-0.7Zr新型铝合金力学性能及微观组织

Mechanical properties and microstructure of novel aluminum alloy Al-6Mg-0.7Zr

采用快速凝固-粉末冶金工艺制备Al-6Mg-0.7Zr新型中高强铝合金。通过室温拉伸、高温拉伸、SEM和TEM等手段对退火态Al-6Mg-0.7Zr合金的力学性能及组织变化进行分析研究。结果表明:快速凝固-粉末冶金法能够突破Zr元素在Al基体中的固溶极限,可制备出质量分数0.7%Zr的新型铝合金。均匀析出的Al_(3)Zr粒子能有效阻碍位错运动,纳米尺度的Al_(3)Zr与基体晶格呈共格关系也有利于合金强度提升。室温下Al-6Mg-0.7Zr合金的抗拉强度达到445 MPa,屈服强度338 MPa,断后伸长率20.10%。此外,Al_(3)Zr粒子在高温下稳定,对晶界迁移及位错运动都有显著阻碍作用,使得合金在200℃以下具有良好的高温性能。150℃下Al-6Mg-0.7Zr合金抗拉强度达到320 MPa,屈服强度266 MPa,断后伸长率33.37%。

A novel medium-to-high strength aluminum alloy Al-6Mg-0.7Zr was prepared by using the rapid solidification-powder metallurgy process.The mechanical properties and microstructural changes of the annealed alloy were analyzed and studied through the methods,such as room temperature tensile testing,high temperature tensile testing,SEM and TEM.The results indicate that by using the rapid solidification-powder metallurgy method,the maximum solid solubility of Zr in the Al matrix is exceeded,and the successful preparation of a 0.7%Zr(mass fraction)alloy is achieved.The Al_(3)Zr particles precipitated during the annealing process exhibit a coherent relationship with the matrix,contributing to the strength enhancement of the alloy.The nano-scale Al_(3)Zr particles play a significant role in improving the strength of the Al-6Mg-0.7Zr alloy.At room temperature,the tensile strength of the Al-6Mg-0.7Zr alloy reaches 445 MPa,with the yield strength of 338 MPa and the post-fracture elongation of 20.10%.In addition,Al_(3)Zr particles remain stable at high temperatures and exhibit significant hindrance to grain boundary migration and dislocation movement,thus providing the alloy with excellent high-temperature performance within temperatures below 200℃.At 150℃,the tensile strength of Al-6Mg-0.7Zr alloy reaches 320 MPa,the yield strength is 266 MPa and the elongation after fracture is 33.37%.