Processing and tensile properties of A356 composites containing in situ small-sized Al3Ti particulates
Processing and tensile properties of A356 composites containing in situ small-sized Al3Ti particulates
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含有原位小尺寸 Al3Ti 颗粒的 A356 复合材料的加工和拉伸性能
DOI：
10.1016/j.msea.2017.11.005
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发表时间：
2018-01-05
期刊：
影响因子：
6.4
通讯作者：
Gao, Yimin
中科院分区：
文献类型：
--
作者：
Liu, Zhiwei;Cheng, Na;Gao, Yimin
本研究提出了在800℃下向A356熔体中加入Ti粉末制备高强度、高延展性Al3Tip/A356复合材料的原位铸造方法。首先进行了取样实验，探索Ti粉末在A356熔体中的演化过程。在此基础上分别制备了Ti添加量为1.5 wt%和3.0 wt%的原位Al3Tip/A356复合材料。研究了T6热处理后试样的显微组织和拉伸性能。结果表明，在原位反应中合成了块状si取代Al3Ti颗粒，其形成遵循反应剥离模型。制备过程中钛粉的利用率可达70%以上。在A356合金α - al晶体内部存在原位Al3Ti颗粒，尺寸小于10 pm。由于Al3Ti的成核作用，长柱状枝晶结构的等轴转变和a-Al晶体的细化都发生了。与T6-A356相比，T6A356/3的屈服强度、极限抗拉强度和伸长率均有所提高。OTi分别提高29.2%、36.0%和143.6%。本文还讨论了复合材料抗拉性能（包括强度和延性）提高的机理。
This research proposed an in situ casting method for preparing Al3Tip/A356 composites with high strength and good ductility by adding Ti powders into molten A356 at 800 degrees C. A sampling experiment was firstly carried out to explore the evolution process of Ti powders in the A356 melt. Based on which in situ Al3Tip/A356 composites with 1.5 and 3.0 wt% Ti additions were fabricated respectively. Both the microstructures and tensile properties of samples after T6 heat treatment were investigated. The results showed that blocky Si-substituted Al3Ti particulates were synthesized in the in situ reaction and the formation of which followed a reaction-peeling model. The utilization ratio of Ti powders in the fabricating process could research 70%. In situ Al3Ti particulates existed inside the alpha-Al crystals of A356 alloy, with the size smaller than 10 pm. Both the equiaxed transition from long columnar dendrite structure and refining of a-Al crystals occurred due to the nucleating effect of Al3Ti. Compared with T6-A356, the yield strength, ultimate tensile strength, and percent elongation of the T6A356/3.OTi were improved by 29.2%, 36.0% and 143.6%, respectively. The mechanisms of the improved tensile properties, including the strength and ductility, of the composites were also discussed in this research.