Magnesium alloys are widely employed in various applications due to their high strength-to-weight ratio and superior mechanical properties as compared to unalloyed Magnesium. Alloying is considered an important way to enhance the strength of the metal matrix composite but it significantly influences the damping property of pure magnesium, while controlling the rate of corrosion for Mg-based material remains critical in the biological environment. Therefore, it is essential to reinforce the magnesium alloy with a suitable alloying element that improves the mechanical characteristics and resistance to corrosion of Mg-based material. Biocompatibility, biodegradability, lower stress shielding effect, bio-activeness, and non-toxicity are the important parameters for biomedical applications other than mechanical and corrosion properties. The development of various surface modifications is also considered a suitable approach to control the degradation rate of Mg-based materials, making lightweight Mg-based materials highly suitable for biomedical implants. This review article discusses the various binary and ternary Mg alloys, which are mostly composed of Al, Ca, Zn, Mn, and rare earth (RE) elements as well as various non-toxic elements which are Si, Bi, Ag, Ca, Zr, Zn, Mn, Sr, Li, Sn, etc. The effects of these alloying elements on the microstructure, the mechanical characteristics, and the corrosion properties of Mg-based materials were analyzed. The mechanical and corrosion behavior of Mg-based materials depends upon the percentage of elements and the number of alloying elements used in Mg. The outcomes suggested that ZEK100, WE43, and EW62 (Mg-6% Nd-2% Y-0.5% Zr) alloys are effectively used for biomedical applications, having preferable biodegradable, biocompatible, bioactive implant materials with a lower corrosion rate.

Particulate-reinforced metal matrix composites are of particular interest because of their ease of fabrication, low cost, and isotropic properties. Friction stir processing offers a promising alternative in the fabrication of surface as well as bulk metal matrix composites. Its very nature aids in the microstructural refinement of the matrix material, avoids the formation of detrimental phases and provides flexible control of the process. Over the period, the technique was successfully applied in the synthesis of various composites. This paper conducts a critical review of the current trends and strategies used to enhance friction stir process efficiency during fabrication of particulate metal matrix composites. It discusses a few of the key underlying principles necessary for making the right combination of matrix and reinforcement. The exhaustive comparative study presented in this article helps in identifying matrix/reinforcement combinations that are yet to be addressed. In the end, a few crucial observations are summarized and important suggestions are provided for future work.

This review article focuses on the aluminum-based metal matrix composites (Al-based MMCs). Studies or investigations of their mechanical and tribological properties performed by researchers worldwide in the past are presented in detail. The processing techniques and applications for Al-based MMCs are also documented here. A brief background on the composite materials, their constituents, and their classification, as well as the different matrix materials and particulates used in Al-based MMCs, can be found in this review. Then, an overview of dual-particle-size reinforced composites, heat treatment of Al alloys, and temper designations used in heat treatment are also included. In addition, the factors influencing the mechanical and wear properties of Al-based MMCs are discussed. The primary objective is that both present and future researchers and investigators will be assisted by the comprehensive knowledge compiled in this article to further explore and work towards the betterment of society in general.

Friction stir welding (FSW) is a solid state joining process which uses a rotating tool consisting of a shoulder and a pin/probe. The shoulder applies a downward pressure to the work piece surface, generates heat through the friction and leads to plasticization of materials in the vicinity of pin. During traverse the rotating tool mixes the adjacent material in the stir zone, creating a joint without fusion. The welding tool pin profile plays a major role in obtaining desirable weld. At present, research efforts are being made to gain a better understanding of the process, to explore different tool configurations, to optimize the set of process parameters and to widen the applicability of FSW and it variants. In this regard, having reliable finite element model that is capable of simulating FSW with minimal possible simulation time can turn out handy to reduce the number of physical experiments required in such studies and applications. The current work investigates a model based approach in knowing the effect of various tool pin profiles on temperature, stir zone and power consumed for welding. A three-dimensional (3-D) model is developed in finite element (FE) commercial code ABAQUS/Explicit using the Coupled Eulerian-Lagrangian (CEL) formulation, the Johnson-Cook material law and Coulomb's law of friction. The obtained results help in arriving at better tool designs