在750°C至1100°C之间的三元化Co-Al-W中,相位平衡和微观结构的演变
Eric A Lass1, Richard D Grist1, Maureen E Williams1
1Materials Science & Engineering Division, National Institute of Standards and Technology, 100 Bureau Dr., M/S 8555, Gaithersburg, MD 20899 USA.
Journal of phase equilibria and diffusion
|November 15, 2024
概括
这项研究绘制了Co-Al-W合金中的相位平衡,揭示了在900°C以下的主导的三相区域. 这项研究澄清了玛原相的稳定性,这对于合金性能至关重要.
科学领域:
- 材料科学 材料科学 材料科学
- 金工业是金工业的一个方面.
- 物理化学 物理化学
背景情况:
- 了解-- (Co-Al-W) 等三元合金中的相位平衡对于开发先进材料至关重要.
- Co-Al-W 系统的 Co-rich 部分对高温应用有兴趣,但详细的相位图不完整.
研究的目的:
- 在750°C和1100°C之间的Co-Al-W系统的Co-rich区域研究相位平衡.
- 为了确定这个温度范围内的玛素 (γ') 阶段的稳定性和转换动力学.
- 提供必要的数据,以开发一个新的热力学描述的三元 Co-Al-W 系统.
主要方法:
- 在Co-rich Co-Al-W系统中,对五种三元合金组合物的异热化.
- 在不同温度 (750°C~1100°C) 下进行微结构分析和相位识别.
- 阶段图和时间-温度-转换 (TTT) 图的异热部分的构造.
主要成果:
- 在900°C以下,相位图的特征是三相连接三角形,其中包括玛 (γ),D019和B2相.
- 在1000°C和1100°C,不同的 γ,D019,B2 和微相组合在图中占据主导地位.
- 玛素 (γ') 阶段表现出有限的稳定性,其持久性可能受到动力学因素的影响,而不是在较高温度下的热力学稳定性.
- 一个TTT图表显示了一个鼻子形状,表明了热力学和动力学之间的权衡 γ'阶段转换.
结论:
- 富含Co-Al-W系统中的相位平衡已经在一个显著的温度范围内被绘制出来.
- γ'阶段的稳定性受到约束,其在微观结构中的存在往往是动力控制的.
- 生成的相图数据和TTT信息对于完善Co-Al-W系统的热力学模型和指导合金设计至关重要.
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