Lei Pan, Zhigang Sun, Xuming Niu, Jiaoling Shi, Yingdong Song
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引用次数: 0
Abstract
SiC fiber reinforced titanium alloy matrix composites employed in elevated temperature aeroengine components are subjected to complex loading conditions. Investigating the shear performance of SiC fibers after heat treatment can help ensure the load-carrying capability of composites at service temperatures. This study presents a novel double shear testing method for W-core SiC fibers. The shear strength and stiffness of the SiC fibers in as-received and heat-treated conditions were measured. The morphologies of SiC fibers’ shear fracture surfaces and C coatings were thoroughly analyzed. The evolution of the internal microstructure and the composition of reaction layers after heat treatments were investigated. The shear strength of W-core SiC fibers at 95% survival probability reached 588.64 MPa after 200 h of heat treatment at 600 °Celsius, representing a 55% improvement over both the as-received and 1100 °Celsius heat-treated conditions. After heat treatment at 1100 °Celsius, the reaction layer between the W core and the SiC sheath thickened exponentially due to extensive elemental diffusion, resulting in the formation of numerous Kirkendall voids. The voids facilitated crack initiation and propagation, leading to a deterioration in fiber shear performance. The insights gained in this study regarding the shear properties of SiC fibers can provide support for predicting the mechanical performance of composites under complex loading conditions.
高温航空发动机部件中使用的碳化硅纤维增强钛合金基复合材料需要承受复杂的负载条件。研究热处理后碳化硅纤维的剪切性能有助于确保复合材料在使用温度下的承载能力。本研究提出了一种针对 W 型芯碳化硅纤维的新型双剪切测试方法。测量了碳化硅纤维在原样和热处理条件下的剪切强度和刚度。对 SiC 纤维剪切断裂面和 C 涂层的形态进行了深入分析。研究了热处理后内部微观结构的演变和反应层的组成。在 600 °C 下热处理 200 小时后,存活率为 95% 的 W 芯 SiC 纤维的剪切强度达到 588.64 MPa,比原样和 1100 °C 热处理条件下的剪切强度提高了 55%。在 1100 ℃ 下进行热处理后,W 内核和碳化硅护套之间的反应层由于大量元素扩散而呈指数级增厚,从而形成了大量 Kirkendall 空隙。这些空隙有利于裂纹的产生和扩展,导致纤维剪切性能下降。本研究中获得的有关碳化硅纤维剪切性能的见解可为预测复合材料在复杂加载条件下的机械性能提供支持。
期刊介绍:
The Lancet Diabetes & Endocrinology, an independent journal with a global perspective and strong clinical focus, features original clinical research, expert reviews, news, and opinion pieces in each monthly issue. Covering topics like diabetes, obesity, nutrition, and more, the journal provides insights into clinical advances and practice-changing research worldwide. It welcomes original research advocating change or shedding light on clinical practice, as well as informative reviews on related topics, especially those with global health importance and relevance to low-income and middle-income countries. The journal publishes various content types, including Articles, Reviews, Comments, Correspondence, Health Policy, and Personal Views, along with Series and Commissions aiming to drive positive change in clinical practice and health policy in diabetes and endocrinology.