The fatigue life of aerospace components depends greatly on the mechanical properties of the finished surface layer. However, no independent strength test of this layer has been reported because of the lack of suitable samples. Therefore, a direct method of assessing the surface tensile strength using film samples with thicknesses of approximately 40 μm is proposed in this paper. The immediate objective of this research is to demonstrate the fundamentals of surface strength testing and prove the feasibility of preparing films by tracking the evolution of the surface integrity. The test results show that layer‐by‐layer grinding and polishing is a feasible method for preparing film samples with sufficient area, controllable thickness, and well‐maintained surface integrity. During the preparation of the film samples, the roughness and micro‐hardness of the test side (the side kept unprepared for testing) are protected, and those of the processed side (the side that is ground and polished) are controlled. The residual stress on both sides is released to zero. The film specimens exhibit regular fracture behaviour in the tensile tests, and their stress–strain curves can be explained as weighted averages of the stress–strain functions of multiple layers.

中文翻译：

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一种使用钛合金Ti-1023上的薄膜样品评估金属表面强度的方法

航空航天部件的疲劳寿命在很大程度上取决于最终表面层的机械性能。然而，由于缺乏合适的样品，没有关于该层的独立强度测试的报道。因此，本文提出了一种使用厚度约为40μm的薄膜样品评估表面抗张强度的直接方法。这项研究的近期目标是证明表面强度测试的基础，并通过跟踪表面完整性的演变来证明制备薄膜的可行性。测试结果表明，逐层研磨和抛光是制备具有足够面积，可控制厚度和良好维护表面完整性的薄膜样品的可行方法。在胶片样品的制备过程中，保护了测试面（未准备进行测试的一面）的粗糙度和显微硬度，并控制了加工面（经研磨和抛光的一面）的粗糙度和显微硬度。两侧的残余应力均释放为零。薄膜试样在拉伸试验中表现出规则的断裂行为，其应力-应变曲线可以解释为多层应力-应变函数的加权平均值。