Grain refinement of gravity die cast secondary AlSi7Cu3Mg alloys for automotive cylinder heads

作     者：Giordano CAMICIA Giulio TIMELLI Giordano CAMICIA;Giulio TIMELLI

作者机构：Department of Management and EngineeringUniversity of Padova 

出 版 物：《Transactions of Nonferrous Metals Society of China》 (中国有色金属学报（英文版）)

年 卷 期：2016年第26卷第5期

页      面：1211-1221页

核心收录：

学科分类：080503[工学-材料加工工程] 080703[工学-动力机械及工程] 08[工学] 0806[工学-冶金工程] 0818[工学-地质资源与地质工程] 0807[工学-动力工程及工程热物理] 0815[工学-水利工程] 0805[工学-材料科学与工程（可授工学、理学学位）] 0813[工学-建筑学] 0703[理学-化学] 0802[工学-机械工程] 0814[工学-土木工程] 0702[理学-物理学] 080201[工学-机械制造及其自动化] 

主　　题：aluminium alloy grain refinement step casting cylinder head cooling rate microstructure mechanical properties 

摘      要：The effects of AITi5B1 grain refinement and cooling rate on the microstructure and mechanical properties of a secondary AlSi7Cu3Mg alloy were reported. Metallographic and image analysis techniques have been used to quantitatively examine the macrostructural and microstructural changes occurring with the addition of grain-refining agent at different cooling rates by using a step casting die. The results indicate that the addition of AlTi5B1 produces a fine and uniform grain structure throughout the casting and this effect is more pronounced in the slowly solidified regions. Increasing the cooling rate, lower amount of grain refiner is necessary to produce a uniform grain size throughout the casting. On the other hand, the initial contents of Ti and B, present as impurity elements in the supplied secondary alloy, are not sufficient to produce an effective grain refinement. The results from the step casting geometry were applied to investigate a gasoline 16V cylinder head, which was produced by gravity semi-permanent mould technology. The grain refinement improves the plastic behaviour of the alloy and increases the reliability of the casting, as evidenced by the Weibull statistics.