Microstructure of Al-Cu Alloy in Rapid Solidification by CO_2 Laser

CO_2激光快速凝固Al-Cu合金的显微组织

• 批准号: 06650832
• 负责人: MIYATA Yasunori
• 金额: $ 1.09万
• 依托单位: Nagaoka University of Technology
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for General Scientific Research (C)
• 财政年份: 1994
• 资助国家: 日本
• 起止时间: 1994 至 1995
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/en/grant/KAKENHI-PROJECT-06650832/
• 关键词: rapid solidification; laser; absolute stability; alloy; dendrite; cellular structure; エネルギー吸収率; 冷却速度; ミクロ組織; セル界面; 絶対安定

New microstructure of alloy is expected to be in rapid solidification, when the melt solidify in its growth rate close to the the absolute stability limit. This limiting growth rate is reached if the growth rate approaches to the speed of diffusion of the solute. The purpose of this work is to study the relation between the microstructure and solidification condition in rapid solidification of Al-Cu alloy.Low solute Al-Cu alloy is used in this experiment. It makes easy to realize the absolute stability condition and it also makes easy to cbserve the microstructure, because low colute concentration will result larger microstructure of alloy. High power CO_2 laser (Max. 6KW) is used to melt and solidify rapidly, and rapid solidification with a few meter per second is realized. The temperature distribution in the melt is studied by numerical analysis MARC.In terms of this distribution the temperature gradient and the growth rate at the solid-liquid interface is obtained.Cellular microstructure is found in Al-0.5 mol%Cu alloy, which is solidified with growth rate 1.7 m/sec. This growth rate is very close to the absolutely stable growth rate of this alloy, which is predicted to be 2.4m/sec by the pertubative theory. Other alloys with thjeir solute concentration 1.0 and 4.5mol%Cu alloy do not show cellular structure but dendritic microstructure. The diameter of the primary stem decreases with growth rate by power-1/2.

当融化的生长速率接近绝对稳定性极限时，合金的新微观结构预计将处于迅速凝固。如果生长速率接近溶质的扩散速度，则达到这种限制生长速率。这项工作的目的是研究al-Cu合金快速凝固的微观结构和凝固条件之间的关系。在本实验中使用低溶质Al-Cu合金。它很容易实现绝对稳定性条件，并且也很容易cbs保存微结构，因为低结肠浓度会导致合金的更大的微观结构。高功率CO_2激光器（最大6kW）用于快速融化和固化，并实现每秒几米的快速固化。通过数值分析MARC研究熔体中的温度分布。在此分布的术语中，温度梯度和固液界面处的生长速率可获得。细胞微观结构可在Al-0.5 mol％CU合金中发现，该合金以1.7 m/sec的生长速率固化。这种增长率非常接近这种合金的绝对稳定增长率，通过透性理论预计为240万/秒。具有Thjeir溶质浓度1.0和4.5mol％Cu合金的其他合金不会显示细胞结构，而是树突状微结构。主茎的直径随着功率1/2的增长速度而降低。