Abstract This paper concerns the use of a recently-developed methodology for inferring stress-strain curves from indentation data, based on iterative FEM simulation of the procedure. A relatively large indenter (2 mm diameter) is used, with deep penetration (to about 25% of the indenter radius). This has been carried out on (polished) free surfaces of sprayed superalloy overlayers on single crystal superalloy substrates. Both load-displacement data and residual indent profiles were obtained, with the overlayers being in two different conditions (as-sprayed and annealed). The overlayers were relatively thick (∼2.5 mm), so it was also possible to carry out uniaxial compression tests on them (in the through-thickness direction). The inferred stress-strain curves were similar in each case when derived from load-displacement data and indent profiles, and also close to the plots obtained by conventional uniaxial testing. The yield stress levels in both cases were around 1000 MPa, but the work hardening rate was significantly higher for the as-sprayed material. This kind of information is of considerable potential value when attempting to optimize the properties of such overlayers. The procedure can be employed, with some confidence, to cases for which uniaxial testing is difficult or impossible.

中文翻译：

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通过压痕测试获得的高温合金基材上喷涂覆层的机械性能

摘要 本文涉及使用最近开发的方法从压痕数据推断应力-应变曲线，基于程序的迭代 FEM 模拟。使用相对较大的压头（直径为 2 毫米），具有较深的穿透力（达到压头半径的 25% 左右）。这是在单晶高温合金基材上喷涂的高温合金覆盖层的（抛光）自由表面上进行的。获得了载荷位移数据和残余压痕轮廓，覆盖层处于两种不同的条件（喷涂和退火）。覆盖层相对较厚（~2.5 mm），因此也可以对其进行单轴压缩试验（沿厚度方向）。当从载荷-位移数据和压痕轮廓导出时，推断的应力-应变曲线在每种情况下都相似，并且也接近通过传统单轴测试获得的图。两种情况下的屈服应力水平都在 1000 MPa 左右，但喷涂材料的加工硬化率明显更高。在尝试优化此类覆盖层的属性时，此类信息具有相当大的潜在价值。该程序可用于单轴测试困难或不可能的情况，有一定的信心。