带在NbTaTiHf耐火中合金中促进了异常的抗破性
David H Cook1,2, Punit Kumar2, Madelyn I Payne1,2
1Department of Materials Science and Engineering, University of California, Berkeley, CA, USA.
Science (New York, N.Y.)
|April 11, 2024
概括
这项研究显示,耐火合金NbTaTiHf在高温下具有异常强度. 这是由于独特的脱位机制,提高了体中心立方合金的柔性和损伤耐受性.
科学领域:
- 材料科学
- 金属工程
- 固体机械学
背景情况:
- 体中心立方体 (bcc) 耐火中高合金在高温下具有高压力强度.
- 然而,这些合金通常具有较差的拉伸性和断裂性,限制了它们的应用.
- 开发具有在高温下改进机械性能的先进合金对于苛刻的工程应用至关重要.
研究的目的:
- 为了研究NbTaTiHf bcc耐火合金的温度依赖强度和断裂性.
- 阐明对观察到的机械行为负责的潜在机制,特别是断裂性.
- 了解脱位动力学如何影响耐火高合金的可塑性和断裂.
主要方法:
- 在广泛的温度范围内对NbTaTiHf合金进行实验测试 (77 K至1473 K).
- 使用已确定的方法 (例如,MPa·m1/2) 分析断裂性.
- 使用先进的显微镜和机械建模,对裂纹尖端的脱位行为进行微结构性表征和分析.
主要成果:
- 在测试温度范围内,NbTaTiHf合金的破裂度超过253 MPa·m1/2.
- 在裂纹尖端螺丝和边缘脱位之间的动态竞争被确定为关键机制.
- 边缘位移的协调滑动,形成曲带,长时间的不均应变和分散的损伤.
结论:
- NbTaTiHf合金克服了bcc耐火合金典型的低性和断裂性限制.
- 独特的脱位可塑性机制,包括曲带的形成,对于增强骨折性和应变适应性至关重要.
- 这项研究为设计适用于极端环境的高性能耐火合金提供了洞察力.
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