Abstract This comparative study sheds light on the optimum addition x of K5[SiFe(OH2)W11O39]·14H2O ({FeSiW11}) and K6[(H2O)MnSiW11O39]·21H2O ({MnSiW11}) (x = 0.02, 0.04, 0.08, 0.12, 0.16 and 0.20 wt%) nanoparticles to produce the desired mechanical characteristics of the (Bi,Pb)-2223 superconducting phase using a Vickers microhardness (HV) tester. HV measurement was performed at room temperature for different applied loads (0.245–9.8 N) and times (10–60 s). From the HV measurements, all the prepared samples had a normal ‘indentation size effect’ behaviour. It was found that 0.04 wt% {FeSiW11} nanoparticles and 0.08 wt% {MnSiW11} nanoparticles were the optimal addition to increase the microhardness of the (Bi,Pb)-2223 phase. Accordingly, other mechanical parameters for potential applications, such as the elastic modulus, yield strength and fracture toughness of the samples studied, were extracted from HV as a function of nanoparticle addition. The measured HV data were theoretically analysed with use of different models. The modified proportional sample resistance model was identified as the best theoretical model to describe the true HV values for both phases. Indentation creep analysis was also performed using time-dependent microhardness to indicate the enhancement of new cavity formation in the measured samples.

中文翻译：

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添加两种过渡金属取代的多金属氧酸盐对(Bi,Pb)-2223超导相力学性能影响的比较研究

摘要 本对比研究揭示了 K5[SiFe(OH2)W11O39]·14H2O ({FeSiW11}) 和 K6[(H2O)MnSiW11O39]·21H2O ({MnSiW11}) (x = 0.02, 0.04, 0.0.0. 、0.12、0.16 和 0.20 wt%) 纳米粒子以使用维氏显微硬度 (HV) 测试仪产生 (Bi,Pb)-2223 超导相所需的机械特性。HV 测量在室温下针对不同的施加载荷 (0.245–9.8 N) 和时间 (10–60 s) 进行。从 HV 测量结果来看，所有制备的样品都具有正常的“压痕尺寸效应”行为。发现 0.04 wt% {FeSiW11} 纳米颗粒和 0.08 wt% {MnSiW11} 纳米颗粒是提高 (Bi,Pb)-2223 相显微硬度的最佳添加物。因此，潜在应用的其他机械参数，例如弹性模量，所研究样品的屈服强度和断裂韧性是从 HV 中提取的，作为纳米颗粒添加的函数。使用不同的模型对测得的高压数据进行了理论分析。改进的比例采样电阻模型被认为是描述两相真实 HV 值的最佳理论模型。还使用与时间相关的显微硬度进行压痕蠕变分析，以表明测量样品中新空腔形成的增强。