Changes in the microstructure and mechanical properties of additively manufactured AlSi10Mg alloy after exposure to elevated temperatures
Changes in the microstructure and mechanical properties of additively manufactured AlSi10Mg alloy after exposure to elevated temperatures
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DOI：
10.1016/j.matchar.2018.01.028
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发表时间：
2018-03-01
影响因子：
4.7
通讯作者：
Vojtech, Dalibor
中科院分区：
文献类型：
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作者：
Fousova, Michaela;Dvorsky, Drahomir;Vojtech, Dalibor
AlSi10Mg 合金的增材制造 (AM) 已成为人们广泛关注的主题，特别是对于发动机中复杂零件的生产。由于此类零件在运行过程中可能会暴露在高温下，因此材料稳定性非常重要，但迄今为止，人们对其与增材制造相关的情况知之甚少。在这里，我们研究了通过选择性激光熔化 (SLM) 生产的 AlSi10Mg 合金在暴露于 120 至 180 摄氏度之间的温度后的变化。在每个温度下，测量硬度演变，硬度随着时间的推移而增加。选择在 160 摄氏度下获得的最大硬度状态进行进一步研究，包括通过扫描和透射电子显微镜进行微观结构分析、化学成分分析和机械性能评估。透射显微镜显示纳米级针状沉淀物导致合金的屈服强度略有增加，同时伸长率显着下降。电子能量损失光谱（EELS）和能量色散光谱（EDS）表明沉淀物令人惊讶地由纯硅组成。为了进行比较，应用了传统的热处理方案（应力消除和 T6）。尽管机械性能损失相当大，但不再观察到热不稳定性。总的来说，我们的结果表明工作温度是确保平稳运行的关键因素
The additive manufacture (AM) of the AlSi10Mg alloy has become the subject of considerable attention, especially for production of complex parts in engines. Because such parts can be exposed to elevated temperatures during operation, material stability is very important, but as yet little is known about it in relation to AM. Here, we studied changes of the AlSi10Mg alloy produced by selective laser melting (SLM) after its exposure to temperatures between 120 and 180 degrees C. At each temperature, hardness evolution was measured, with hardness increasing over time. The maximum hardness state obtained at 160 degrees C was selected for further studies comprising microstructural analysis by scanning and transmission electron microscopy, chemical composition analysis and mechanical properties assessment. Transmission microscopy revealed nano-scale acicular precipitates that caused a slight increase in the yield strength of the alloy together with a significant drop in elongation. Electron energy loss spectroscopy (EELS) and energy dispersive spectroscopy (EDS) showed that the precipitates surprisingly consisted of pure Si. To provide a comparison, conventional regimes of heat treatment (stress-relief and T6) were applied. Despite a considerable loss in mechanical performance, thermal instability was no longer observed. Overall, our results indicate that operating temperatures are a key factor in ensuring the smooth operation