Breaking through the strength-ductility trade-off dilemma in an Al-Si-based casting alloy.
Breaking through the strength-ductility trade-off dilemma in an Al-Si-based casting alloy.
复制标题
突破铝硅基铸造合金的强度与延展性权衡困境
DOI：
10.1038/srep30874
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发表时间：
2016-08-09
影响因子：
4.6
通讯作者：
Liu F
中科院分区：
文献类型：
--
作者：
Dang B;Zhang X;Chen YZ;Chen CX;Wang HT;Liu F
Al-Si基铸造合金在各种工业应用中具有巨大的潜力。这些合金的常用强化策略不可避免地伴随着延性的牺牲，称为强度-延性权衡困境。在这里，我们报告了一个简单的路线相结合的快速凝固（RS）与凝固后热处理（PHT），即RS + PHT路线，以打破这一困境，使用商业铝硅基铸造合金（A356合金）为例。结果表明，通过提高RS后的冷却速度，RS + PHT处理合金的屈服强度和断裂伸长率同时提高，而T6热处理对屈服强度和断裂伸长率的影响不大。突破困境归因于RS + PHT路线形成的分级组织，即高度分散的纳米Si颗粒在Al枝晶中，纳米Al颗粒装饰在共晶Si中。RS + PHT路线的简单性使其适合于工业规模生产。微观结构工程化的策略为其他铝硅基合金的力学性能定制提供了一条通用的途径。此外，A356合金的显著增强的延展性不仅允许通过加工硬化进一步强化材料，而且还可能使材料的常规固态成形成为可能，从而扩展了这种合金的应用。
Al-Si-based casting alloys have a great potential in various industrial applications. Common strengthening strategies on these alloys are accompanied inevitably by sacrifice of ductility, known as strength-ductility trade-off dilemma. Here, we report a simple route by combining rapid solidification (RS) with a post-solidification heat treatment (PHT), i.e. a RS + PHT route, to break through this dilemma using a commercial Al-Si-based casting alloy (A356 alloy) as an example. It is shown that yield strength and elongation to failure of the RS + PHT processed alloy are elevated simultaneously by increasing the cooling rate upon RS, which are not influenced by subsequent T6 heat treatment. Breaking through the dilemma is attributed to the hierarchical microstructure formed by the RS + PHT route, i.e. highly dispersed nanoscale Si particles in Al dendrites and nanoscale Al particles decorated in eutectic Si. Simplicity of the RS + PHT route makes it being suitable for industrial scaling production. The strategy of engineering microstructures offers a general pathway in tailoring mechanical properties of other Al-Si-based alloys. Moreover, the remarkably enhanced ductility of A356 alloy not only permits strengthening further the material by work hardening but also enables possibly conventional solid-state forming of the material, thus extending the applications of such an alloy.