In recent years, medium manganese steels (MMSs) have garnered increased attention and interest due to their relatively low cost and superior combination properties compared to other steels. In particular, MMSs have been recognised as ideal wear-resistant materials employed in the mining industry. However, the studies on their wear performance have a lack of systematic documentation. This review provides an extensive overview of recent advances in the wear performance of MMSs, starting from discussions on applicable wear testing methods and typical wear testing results, followed by a further discussion on the wear mechanisms of MMSs based on five wear characteristics, including abrasive wear, adhesive wear, corrosive wear, fatigue wear and impact wear. The effects of hardness and hardened layers on the wear mechanisms are also discussed. Finally, the influence of phase constitution and microstructure on the wear performance of MMSs are comprehensively elaborated in terms of transformation induced plasticity (TRIP), twinning induced plasticity (TWIP), alloy elements and heat treatment. The key factors that affect the wear performance of MMSs include the elemental composition in MMSs and the phase transformation occurred during TRIP and TWIP as well as various heat treatment processes. The current review of key factors affecting the wear performance of MMSs sheds some light on new strategies to enhance the service performance and longevity of wear resistant steels in various engineering applications.

Micro deep drawing (MDD) is a fundamental process in microforming which has wide applications in micro electromechanical system (MEMS) and biological engineering. Titanium possesses excellent mechanical properties and biocompatibility, which makes it a preferred material in micromanufacturing. In this study, eco-friendly and low-cost water-based TiO2 nanolubricants were developed and applied in the MDD with 40 μm-thick pure titanium foils. The lubricants consisting of TiO2 nanoparticles (NPs), 10 wt% glycerol, 0.1 wt% sodium dodecyl-benzene sulfonate (SDBS) and balanced water were synthesised in a facile process. The MDD with 40 μm-thick pure titanium was carried out using the lubricants with varying concentrations of 0.5, 1.0 and 2.0 wt%. The results show that the formability of micro cups could be significantly improved when the nanolubricants are applied. Especially, the use of 1.0 wt% TiO2 nanolubricant demonstrates the best lubrication performance by significantly reducing the final drawing forces, and surface roughness, and the wrinkles by up to 24.2%, 12.55% and 4.82%, respectively. The lubrication mechanisms including the ball bearing and mending effects of NPs on open lubricant pockets (OLPs) and close lubricant pockets (CLPs) areas were then revealed through microstructure observation.