ABSTRACT Sintered iron samples were produced using different pressing loads, resulting in different residual porosities of approximately 14%, 18%, 22% and 30%. Iron-matrix composites, containing 2.5, 5.0, 7.5 and 10.0 %vol. of dispersed hexagonal boron nitride (hBN) particles, were also produced. The influence of these parameters on the amplitude-dependent damping capacity was assessed using a dynamic-mechanical analyser. The simultaneous effect on mechanical strength was assessed through a tensile test. The microstructure was analysed with optical and electronic microscopy and quantitatively evaluated through a digital image analysis. It was verified that the increase of porosity did not lead to a representative increase in the damping capacity of sintered iron. On the other hand, higher hBN content leads to a higher damping capacity due to the introduction of robust new damping mechanisms. However, hBN reservoirs, which are bigger and more elongated than the pores, are more detrimental to mechanical strength.

中文翻译：

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孔隙率和 hBN 含量对金属基复合材料阻尼能力的影响

摘要 烧结铁样品使用不同的压力载荷生产，导致不同的残余孔隙率约为 14%、18%、22% 和 30%。铁基复合材料，含有 2.5、5.0、7.5 和 10.0%vol。还生产了分散的六方氮化硼 (hBN) 颗粒。使用动态机械分析仪评估这些参数对振幅相关阻尼能力的影响。通过拉伸试验评估对机械强度的同时影响。用光学和电子显微镜分析微观结构，并通过数字图像分析进行定量评估。经证实，孔隙率的增加并未导致烧结铁的阻尼能力有代表性的增加。另一方面，由于引入了强大的新阻尼机制，更高的 hBN 含量会导致更高的阻尼能力。然而，比孔隙更大、更细长的 hBN 储层对机械强度的不利影响更大。