Effect of T4 heat treatment on microstructure and hardness of A356 alloy refined by Ga + In + Sn mixed alloy
Effect of T4 heat treatment on microstructure and hardness of A356 alloy refined by Ga + In + Sn mixed alloy
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DOI：
10.1016/j.matdes.2013.12.022
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发表时间：
2014-05-01
影响因子：
8.4
通讯作者：
Liu, M. C.
中科院分区：
文献类型：
--
作者：
Dang, B.;Li, Y. B.;Liu, M. C.
采用Ga + In + Sn混合合金相变冷却（PTC）提高冷却速度的方法对A356合金进行凝固，然后在540 ℃、500 ℃和450 ℃下进行不同时间的固溶处理，然后进行淬火和立即自然时效。研究了相应的显微组织和硬度随固溶温度和时间的变化规律。由于铸态样品的显微组织细化，Si和Mg团簇在Al基体中的溶解度大，以及纳米级的Si析出物，铸态样品被硬化。共晶Si的变质作用取决于Si的初始凝固形态、固溶温度和固溶时间，高冷却速度和高固溶温度下的Si颗粒更容易球化。从硬度测试和差示扫描量热法（DSC）的结果来看，时效硬化与Guinier-Preston（GP）区有关。结果表明，采用最佳的凝固与热处理工艺组合，可以在降低生产成本的同时获得较好的力学性能。2013爱思唯尔有限公司保留所有权利。
A356 alloy was solidified with cooling rate enhanced by phase transition cooling (PTC) of Ga + In + Sn mixed alloy, and then solution treated at 540 degrees C, 500 degrees C and 450 degrees C for different time, followed by quenching and immediately natural aging. Evolution of the corresponding microstructure and hardness with the solution temperature and time were studied. The as-cast sample was hardened due to the refined microstructures, the large solubility of Si-and Mg-clusters in Al matrix and the nano-scale Si precipitates. The modification of eutectic Si was verified to depend on the initially solidified morphology of Si, the solution temperature and time, for example, the Si particles subjected to high cooling rate and high solution temperature become more readily spheroidized. The age hardening, from the hardness tests and differential scanning calorimetry (DSC) results, was ascribed to be associated with the Guinier-Preston (GP) zones. It can be concluded that an optimal combination of solidification with heat treatment may achieve the better mechanical property but with the less product cost. 2013 Elsevier Ltd. All rights reserved.