Metallic hollow spheres are used as base materials in the manufacture of hollow sphere structures and metallic foams. In this study, steel hollow spheres were successfully manufactured using an advanced powder metallu...Metallic hollow spheres are used as base materials in the manufacture of hollow sphere structures and metallic foams. In this study, steel hollow spheres were successfully manufactured using an advanced powder metallurgy technique. The spheres' shells were characterized by optical microscopy in conjunction with microstructural image analysis software, scanning electron microscopy(SEM), energy-dispersive X-ray spectroscopy(EDX), and X-ray diffraction(XRD). The microscopic evaluations revealed that the shells consist of sintered iron powder, sintered copper powder, sodium silicate, and porosity regions. In addition, the effects of copper content on various parameters such as shell defects, microcracks, thickness, and porosities were investigated. The results indicated that increasing the copper content results in decreases in the surface fraction of shell porosities and the number of microcracks and an increase in shell thickness.展开更多
研究了不同石粉含量对C60机制砂混凝土徐变的影响,并对现有徐变预测模型进行了对比分析。结果表明:当机制砂石粉含量不超过15%时,各组试件的抗压强度均可满足C60强度等级的要求,各组试件120 d的徐变应变约为(180~230)×10-6,徐变系...研究了不同石粉含量对C60机制砂混凝土徐变的影响,并对现有徐变预测模型进行了对比分析。结果表明:当机制砂石粉含量不超过15%时,各组试件的抗压强度均可满足C60强度等级的要求,各组试件120 d的徐变应变约为(180~230)×10-6,徐变系数在0.41~0.56之间;随着石粉含量的增加,各组试件的徐变应变呈现先减小后增大的趋势,徐变系数呈先增大后减小的趋势;石粉含量对C60机制砂混凝土徐变的影响不显著;现有徐变模型对徐变系数的计算结果均大于实测结果;相比较之下,fib MC 2010模型更适用于高强机制砂混凝土的徐变预测。展开更多
文摘Metallic hollow spheres are used as base materials in the manufacture of hollow sphere structures and metallic foams. In this study, steel hollow spheres were successfully manufactured using an advanced powder metallurgy technique. The spheres' shells were characterized by optical microscopy in conjunction with microstructural image analysis software, scanning electron microscopy(SEM), energy-dispersive X-ray spectroscopy(EDX), and X-ray diffraction(XRD). The microscopic evaluations revealed that the shells consist of sintered iron powder, sintered copper powder, sodium silicate, and porosity regions. In addition, the effects of copper content on various parameters such as shell defects, microcracks, thickness, and porosities were investigated. The results indicated that increasing the copper content results in decreases in the surface fraction of shell porosities and the number of microcracks and an increase in shell thickness.
文摘研究了不同石粉含量对C60机制砂混凝土徐变的影响,并对现有徐变预测模型进行了对比分析。结果表明:当机制砂石粉含量不超过15%时,各组试件的抗压强度均可满足C60强度等级的要求,各组试件120 d的徐变应变约为(180~230)×10-6,徐变系数在0.41~0.56之间;随着石粉含量的增加,各组试件的徐变应变呈现先减小后增大的趋势,徐变系数呈先增大后减小的趋势;石粉含量对C60机制砂混凝土徐变的影响不显著;现有徐变模型对徐变系数的计算结果均大于实测结果;相比较之下,fib MC 2010模型更适用于高强机制砂混凝土的徐变预测。