ABSTRACT

In the present work, monolithic pure magnesium (Mg) and magnesium with 1.5, 2.5 & 5.0 wt. % of titanium dioxide (TiO₂) nanoparticulate composites were synthesised using powder metallurgy technique followed by two-stage hybrid microwave sintering and hot extrusion at 350°C with an extrusion ratio of 16:1. Mass density, porosity, microstructure, microhardness and compressive strength of the composite were critically investigated as per ASTM standards. Microstructural characterisation reveals the quantitative elements such as Mg, Ti and O, its composition, refined grain size of matrix, grain boundary and uniform distribution of TiO₂ nanoparticles in the magnesium matrix. Mass density and microhardness were observed to increase steadily with increase in addition of TiO₂ nanoparticles. Further, maximum compressive strength was obtained for Mg5TiO₂ composite. Harder and fine grain TiO₂ nanoparticulate was responsible for appreciable mechanical behaviour of composite. Refined magnesium grains also contributed appreciably for significant mechanical behaviour through the nucleation effect.

摘要

在目前的工作中，整体纯镁 (Mg) 和镁具有 1.5、2.5 和 5.0 重量。% 的二氧化钛 (TiO ₂ ) 纳米颗粒复合材料是使用粉末冶金技术合成的，然后是两阶段混合微波烧结和在 350°C 下以 16:1 的挤压比进行热挤压。根据 ASTM 标准，对复合材料的质量密度、孔隙率、微观结构、显微硬度和抗压强度进行了严格的研究。微观结构表征揭示了Mg、Ti和O等定量元素、其组成、基体细化晶粒尺寸、晶界和TiO ₂纳米颗粒在镁基体中的均匀分布。观察到质量密度和显微硬度随着 TiO ₂添加量的增加而稳定增加纳米粒子。此外，Mg5TiO ₂复合材料获得了最大的抗压强度。更硬和细颗粒的 TiO ₂纳米颗粒是造成复合材料显着机械性能的原因。精炼镁晶粒也通过成核效应对显着的机械性能做出了显着贡献。