Delineating brittle-phase embrittlement and ductile-phase toughening in Nb-based in-situ composites
Delineating brittle-phase embrittlement and ductile-phase toughening in Nb-based in-situ composites
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DOI：
10.1007/s11661-001-1024-7
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发表时间：
2001-11
期刊：
影响因子：
--
通讯作者：
K. Chan;D. Davidson
中科院分区：
文献类型：
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作者：
K. Chan;D. Davidson
Nb-basedin-situ复合材料的断裂韧性通常随着硬质金属间相的体积分数的增加而降低，尽管在显微组织中存在韧性铌固溶体相。对于具有连续金属间化合物基体的复合材料，断裂韧性可以是单片金属间化合物的两倍以上，但在绝对值上仍然较低，这表明固溶体相在诱导延性相增韧方面不是非常有效。缺乏增强的抗断裂性似乎是由微观结构中的脆性相引起的脆化效应引起的，其不可变形性导致作用于延性相的高塑性约束。在这篇文章中，一个分析模型，开发处理脆性相脆化和韧性相增韧的组成属性和微观结构变量。该模型可用于描述Nb基原位复合材料的脆性相脆化和塑性相增韧，以及Nb-Ti-Cr、Nb-Ti-Al和Nb-Ti-Si系原位复合材料的设计。
The fracture toughness of Nb-basedin-situcomposites typically decreases with increasing volume fractions of hard intermetallic phases, despite the presence of a ductile niobium solid-solution phase in the microstructure. For composites with a continuous intermetallic matrix, the fracture toughness can be more than double that of the monolithic intermetallics, but is still low in absolute terms, indicating that the solid-solution phase is not very effective in inducing ductile-phase toughening. The lack of enhancement of the fracture resistance appears to arise from an embrittlement effect instigated by the brittle phases in the microstructure, whose nondeformability results in a high plastic constraint acting on the ductile phase. In this article, an analytical model is developed for treating both brittle-phase embrittlement and ductile-phase toughening in terms of constituent properties and microstructural variables. The model is then used to (1) delineate brittle-phase embrittlement and ductile-phase toughening in Nb-basedin-situcomposites, and (2) design fracture-resistantin-situcomposites based on Nb-Ti-Cr, Nb-Ti-Al, and Nb-Ti-Si systems.