高强度Al-Mg-Sc-Zr合金的激光熔化沉积工艺研究

Study on Process Parameters for Preparing a High-Strength Al-Mg-Sc-Zr Alloy by Laser Melting Deposition

基于激光熔化沉积技术制备了高强度Al-Mg-Sc-Zr合金试样,采用金相显微镜、扫描电子显微镜、显微硬度和室温拉伸等试验方法,研究了能量密度和送粉速率对沉积试样的致密度、微观组织演变和力学性能的影响规律。结果表明:在送粉速率一定的条件下,随着能量密度的提高,沉积试样的致密化行为逐渐增强,致密度呈现逐渐升高的趋势。随着送粉速率的提高,趋势愈发显著。在送粉速率为5.5 g/min、能量密度为50~150 J/mm^(2)的条件下,试样致密度从97.88%提高至99.47%。在优化的工艺条件下,即能量密度为100 J/mm^(2)、送粉速率为2.5 g/min时,获得了最优综合力学性能的沉积态试样,其致密度、屈服强度、抗拉强度、延伸率以及显微硬度分别为99.51%、268 MPa、450 MPa、18.4%和120.18 HV0.2。

This study investigated the preparation of highstrength AlMgScZr alloy samples by laser melting deposition technology.The effects of energy density and powder feeding rate modifications on the density,microstructural evolution,and mechanical properties of the deposited samples were investigated using metallographic,scanning electron microscopes,microhardness,and tensile properties at room temperature.Results showed that under a constant powder feeding rate,the deposited samples’densification behavior and density gradually increased with an increase in energy density.This trend became more significant with an increase in the powder feeding rate.Hence,when the powder feeding rate was set to 5.5 g/min,the density of 50‒150 J/mm^(2) samples specifically increased from 97.88%to 99.47%.Nevertheless,the sample with the best comprehensive mechanical properties was deposited under optimized technological conditions,namely an energy density of 100 J/mm^(2) and a powder feeding rate of 2.5 g/min.Its density,yield strength,tensile strength,elongation,and microhardness were 99.51%,268 MPa,450 MPa,18.4%,and 120.18 HV0.2,respectively.