Al–Si–Cu–Mg cast aluminum alloys have important applications in automobile lightweight due to their advantages such as high strength-to-weight ratio, good heat resistance and excellent casting performance. With the increasing demand for strength and toughness of automotive parts, the development of high strength and toughness Al–Si–Cu–Mg cast aluminum alloys is one of the effective measures to promote the application of cast aluminum alloys in the automotive industry. In this paper, the research progress of improving the strength and toughness of Al–Si–Cu–Mg cast aluminum alloys was described from the aspects of multi-component alloying and heat treatment based on the strengthening mechanism of Al–Si–Cu–Mg cast aluminum alloys. Finally, the development prospects of automotive lightweight Al–Si–Cu–Mg cast aluminum alloys is presented.

Magnesium and magnesium-based alloys are widely used in the transportation, aerospace and military industries because they are lightweight, have good specific strength, a high specific damping capacity, excellent electromagnetic shielding properties and controllable degradation. However, traditional as-cast magnesium alloys have many defects. Their mechanical and corrosion properties cause difficulties in meeting application requirements. Therefore, extrusion processes are often used to eliminate the structural defects of magnesium alloys, and to improve strength and toughness synergy as well as corrosion resistance. This paper comprehensively summarizes the characteristics of extrusion processes, elaborates on the evolution law of microstructure, discusses DRX nucleation, texture weakening and abnormal texture behavior, discusses the influence of extrusion parameters on alloy properties, and systematically analyzes the properties of extruded magnesium alloys. The strengthening mechanism is comprehensively summarized, the non-basal plane slip, texture weakening and randomization laws are comprehensively summarized, and the future research direction of high-performance extruded magnesium alloys is prospected.

Due to the spontaneous degradability, excellent biocompatibility, favorable bone−inducibility, and antimicrobial properties, Mg−based alloys acting as miniature intravascular stents and bone−fixation materials have shown great development−potential. Regrettably, the uneven degradation model and excessive dissolution rate restricted their clinical application. In this study, the latest research on five methods (high−purity or amorphous, micro−alloying, heat−treatment, plastic−deformation, and surface modification) in medical Mg alloy degradation behaviors was reviewed. The corrosion mechanisms of Mg alloys under different processes were summarized. In addition, the effects of microstructure characteristics and film−layer features on corrosion resistance were systematically discussed. Ultimately, existing problems and future development directions of medical Mg−based alloys were reviewed.

The poor corrosion resistance of magnesium alloys is one of the major obstacles to their widespread applications in the engineering field and the medical field. A hot deformation process is the main way to improve the corrosion resistance of magnesium alloys. In the present study, X-ray photoelectron spectroscopy (XPS), a scanning electron microscope (SEM), an electron probe micro-analyzer (EPMA) and X-ray diffraction (XRD) were used to investigate the micro-galvanic corrosion behavior and film protection mechanism of hot-rolled Mg-2Zn-2Er-0.3Zr-0.3Mn under 25%, 50% and 75% thickness reductions in Hank’s solution. The results revealed that the best corrosion resistance was obtained in the alloy under a 75% thickness reduction, with a corrosion rate of 0.85 mm/y. The improvement in anti-corrosion was due to the coupling effect of a refined microstructure and dense degradation film on the large deformation hot-rolled alloy. Furthermore, the elements Mn and Er participated in the film formation and stabilized the film structure.