均匀化温度对6005A铝合金铸锭组织性能的影响

The influences of homogenization temperatures on microstructure and properties of 6005A Al alloy ingot

采用金相观察、硬度和电导率测试、扫描电镜观察及能谱分析等方法对6005A铝合金铸锭及不同均匀化温度处理后的铸锭组织进行研究。结果表明:6005A铝合金铸态组织主要由α-Al固溶体和非平衡共晶相组成,第二相主要为Mg_(2)Si、AlFeSi相。在450~500℃均匀化处理时Mg_(2)Si从固溶体中析出。随着均匀化温度继续升高,Mg_(2)Si及非平衡共晶相逐渐回溶到基体中,从α-Al固溶体中析出的Mn、Cr元素与板条状的β-AlFeSi相结合,使板条状的α-AlFeSi相转变为断续球状的α-Al(FeMn)Si相和α-Al(FeMnCr)Si相,铸锭在570℃均匀化效果最佳。随着均匀化温度升高,铸锭硬度先降低后升高再降低,导电率呈现先升高后降低趋势。α-Al基体中析出细小的α-Al(FeMn)Si、Al(FeMnCr)Si弥散相尺寸随均匀化温度的升高逐渐增大。

The influences of homogenization temperatures on the microstructure and properties of 6005A A1 alloy ingot were studied by means of metallographic observation,hardness test,conductivity test,SEM and EDS analysis.The results show that,the as-cast microstructure of 6005 A A1 alloy is mainly composed ofα-Al solid solution and non-equilibrium eutectic phase,and its second phase is mainly Mg_(2)Si and AlFeSi.During 450℃-500℃homogenization treatment,the Mg_(2)Si precipitates from the solid solution.With the continuous increase of homogenization temperature,Mg_(2)Si and non-equilibrium eutectic phase gradually dissolves into the matrix;Mn,Cr elements precipated fromα-Al solid solution combined with the strip-shapedβ-AlFeSi transforms the strip;-shapedβ-AlFeSi phase into discontinuous granularα-Al(FeMn)Si andα-Al(FeMnCr)Si phase;and ingot treated at 570℃has the best homogenization effect.With the increase of the homogenization temperature,the hardness of ingot first decreases,then increases and then decreases.The electrical conductivity first increases and then decreases.Fineα-Al(FeMn)Si andα-Al(FeMnCr)Si dispersion phases are precipitated inα-Al matrix,and the size of homogenization dispersion phase gradually increases with the increase of temperature.