Microstructural characterization of AM60- TixNby nanocomposite powders processed by high-energy ball milling

Magnesium alloys are one of the lightest metal alloys and are considered potential candidates for structural and hydrogen storage applications. High-energy ball milling is an efficient powder metallurgy technique to produce fine composite particles. The AM60 Magnesium alloy was ball milled with different reinforcement concentrations (5Nb,10Nb, 5Ti,10Ti, 3Ti+7Nb, and 3Nb+7Ti) wt% for 10 h and 20 h. The morphology and microstructure were analyzed using a scanning electron microscope equipped with energy dispersive spectrometry and field emission transmission electron microscope. The crystallite size, lattice strain, and solid solubility were analyzed using XRD. It was observed that higher milling time has refined the particle size. The XRD analysis revealed that a maximum crystallite size of 17 nm was observed in the AM60Ti10 composite after 10 h and a minimum of 14 nm in the AM60Ti3Nb7 composite after 20 h milling time. The results revealed that niobium and titanium reduced the crystallite size and enhanced the lattice strain synergistically. The maximum lattice strain (0.066 %) and dislocation density (9 nm⁻²) were observed in the AM60Nb7Ti3 composite after 20 h milling time. The SEM results revealed The AM60Nb10 composite after 20 h presents a minimum particle size of (9 μm), while AM60Ti5 has a maximum particle size of 15 μm after 10 h milling. The Ti addition causes agglomeration and the AM60Ti5 composite has the maximum average particle size of 15 μm after 10 h milling. The SEM results revealed that flattened agglomerates are formed as the result of higher milling energy during the collision.