在Al-Si合金的高压压中扩展剪切带的演变
Jingzhou Lu1, Ewan Lordan2, Yijie Zhang2
1School of Metallurgy and Environment, Central South University, Changsha 410083, China.
Materials (Basel, Switzerland)
|October 26, 2024
概括
合金的高压压 (HPDC) 揭示了控制填充速度优化外部固化晶体 (ESC) 尺寸,最小化缺陷,并通过理解扩张剪切带来最大化机械性能.
科学领域:
- 材料科学 材料科学 材料科学
- 机械工程 机械工程
- 计算流体动力学的流体动力学.
背景情况:
- 高压压件 (HPDC) 经常表现出牙间多孔性和宏观分离.
- 在HPDC合金的半固体状态下扩张的潜在微机理仍然不完全理解.
- 在HPDC中扩展性剪切带与在颗粒材料中观察到的类似.
研究的目的:
- 调查流体流量和外部固化晶体 (ESC) 尺寸对HPDC扩张剪带演变的影响.
- 阐明在HPDC中合金固化过程中控制扩张的微机理.
- 优化HPDC工艺参数,以改善合金微观结构和机械性能.
主要方法:
- 在HPDC中使用不同的填充速度生产Al8SiMnMg合金样本.
- 在不同的流量条件下分析晶体碎片化和剪切带的形成.
- 颗粒物质物理和DEM型建模 (OpenFOAM) 的应用用于微观结构分析.
主要成果:
- 晶体碎片化最初会降低扩展度,导致模糊的剪切带.
- 增加的填充速度 (2.2至4.6m/s) 将扩张局部化为碎片化停滞后集中的剪切带.
- 最佳的活塞速度为3.6 m/s,最大限度地减少ESC大小,最大限度地提高屈服应力 (144.6 MPa) 和强度延长产值 (3.664 GPa%).
结论:
- 在等固合金中,扩张性剪带的演变可以使用颗粒物质概念来解释,例如力链曲.
- 确定了ESC增强扩张的三个机制,澄清了ESC与剪带特征之间的联系.
- 将颗粒物理原理应用于HPDC,为流程优化和微结构建模提供了新的途径.
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