Effect of non-equilibrium heat treatments on microstructure and tensile properties of an Al-Si-Cu alloy
Effect of non-equilibrium heat treatments on microstructure and tensile properties of an Al-Si-Cu alloy
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DOI：
10.1016/j.msea.2016.07.080
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发表时间：
2016-09
期刊：
影响因子：
6.4
通讯作者：
I. Bacaicoa;P. Dwivedi;M. Luetje;F. Zeismann;A. Brueckner-foit;A. Geisert;M. Fehlbier
中科院分区：
文献类型：
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作者：
I. Bacaicoa;P. Dwivedi;M. Luetje;F. Zeismann;A. Brueckner-foit;A. Geisert;M. Fehlbier
研究了热处理对富铁Al-Si-Cu中β-Al5FeSi夹杂物形貌的影响，提高了拉伸性能。样品采用砂型铸造并进行各种 T6 热处理。通过光学显微镜和扫描电子显微镜 (SEM) 检查金相样品，并使用图像分析软件对富铁相的平均长度和面积分数进行量化。研究发现，最低固溶温度为 520–525 °C，固溶时间为 1 小时，才能使有害的长针状 ß-Al5FeSi 夹杂物显着破碎和溶解。固溶时间超过 2 小时会导致富铜相开始熔化和共晶硅粗化。由热处理样品加工出拉伸样品并进行拉伸测试。最高极限拉伸强度对应于在 525°C 下热处理 1.5 小时的样品。断裂表面观察表明未经处理的样品存在穿晶解理机制，并且块状 ß-Al5FeSi 片被确定为主要裂纹萌生位点。热处理后，观察到混合断裂模式和溶解的 ß-Al5FeSi 相。
The influence of heat treatment on the morphology of ß-Al5FeSi inclusions in Fe-rich Al-Si-Cu was investigated and the tensile properties were improved. Samples were sand casted and subjected to various T6 heat treatments. Metallographic samples were examined by optical microscopy as well as scanning electron microscopy (SEM) and the average length and area fraction of the Fe-rich phases were quantified with image analysis software. It was found that a minimum solution temperature at 520–525 °C and solution time of 1 h is required for a significant fragmentation and dissolution of the detrimental long-needle-like ß-Al5FeSi inclusions. Solution time longer than 2 h leads to incipient melting of Cu-rich phases and coarsening of the eutectic Si. Tensile specimens were machined from the heat-treated samples and tensile tests performed. The highest ultimate tensile corresponds to the samples heat treated at 525 °C for 1.5 h. Fracture surface observations indicate a transgranular cleavage mechanism for the non-treated specimens, and massive ß-Al5FeSi platelets were identified as main crack initiation sites. After heat treatment, a mixed fracture mode and dissolved ß-Al5FeSi phases were observed.