Microstructural, Mechanical And Corrosion Properties Of Nano-Structured Az91 Magnesium Alloy Composites Fabricated By Spark Plasma Sintering

Abstract

The study meticulously investigates the synthesis and characterization of nanocrystalline (nc) AZ91 magnesium alloy, achieved through a combination of mechanical ball milling and spark plasma sintering (SPS) techniques. It provides a detailed examination of the microstructural, mechanical, and corrosion behavior properties of the synthesized alloy. Specifically, the impact of an 8-hour ball milling process on grain particle refinement and the development of nanometer-sized grains is thoroughly analyzed. The subsequent sintering process, conducted for the AZ91 alloy at temperatures ranging from 465°C to 565°C using spark plasma sintering, is carefully discussed. Throughout the SPS process, the study observes a uniform distribution of grains with well-defined particle boundaries, and the absence of pores, indicating improved material integrity. Notably, a significant enhancement in mechanical properties, including hardness, tensile strength, and corrosion resistance, is noted in the AZ91 magnesium alloy with increasing sintering temperature. For instance, hardness reaches up to 62 Hv, while the highest UCS recorded is 342 MPa at 425°C, with a strain fracture of about 28%. Corrosion tests reveal the lowest corrosion rate at an Ecorr value of -1.362 mV vs SCE, an icorr value of 14.27 μA.cm⁻², and an rcorr value of 0.35 mm.y⁻¹ during the highest temperatures. This comprehensive exploration highlights the intricate relationship between processing techniques and material properties, underscoring the potential of nanocrystalline AZ91 magnesium alloy for various engineering applications due to its superior mechanical and corrosion-resistant characteristics. It offers valuable insights for further advancements in material science and engineering.