Advanced Production Process and Properties of Die Cast Magnesium Composites Based on AZ91D and SiC

Abstract

The driving force behind the efforts to develop magnesium metal matrix composites (MMC) via high-pressure die casting is the requirements for advanced applications under severe operational conditions in terms of stress, temperature, and corrosion resistance. Therefore this study aims to explore the mechanical properties of die cast Mg-MMC in terms of hardness and strength, as well as its corrosion resistance. AZ91D was chosen as the most commonly used magnesium alloy. The choice as the reinforcement agent that has to be an economical and non-reactive addition was silicon carbide particles (SiC P ) with an average particle size of 10 lm. The challenge was production of high quality, homogeneous material with good mechanical properties and acceptable corrosion resistance. The results revealed the advantages of a die cast Mg-MMC as a new attractive alternative for advanced structural applications that can be used for mass production.

Effect of SiC Reinforcement and Its Variation on the Mechanical Characteristics of AZ91 Composites

“…Furthermore, the density values are found to increase with increasing content of SiC particulate, due to the presence of the comparatively higher density SiC particulate in the magnesium alloy [ 34 ]. The porosity also exhibits a gradual increase as the weight percentage of the reinforcement in the composite increases.…”

Tensile and wear properties of as-cast and extruded AZ91-xCNT and AZ91-1B4C-1SiC-xCNT composites

“…The variation in the porosity of the composites is attributed to processing conditions, the size of reinforcement, and solidification shrinkage during the cooling process. The increase in porosity has caused a decrease in the mechanical behaviour of the MMCs [51,52]. Although some investigations declare that nano-sized particles in a ductile matrix improve mechanical properties, like hardness, no obvious improvement is seen in the hardness results for the cast AZ91-xCNT composite, as shown in Figure 9(a).…”

Filling Characteristics of Magnesium Alloy Molten Metal in Squeeze Casting

“…At present, about 60 percent of magnesium alloy castings have been produced by high-pressure die casting processes. However, the quality of high-pressure die castings can't be improved by heat treatment because of relatively high-gas porosity levels [2,3]. Hence, high-quality castings can't be produced by high-pressure die casting.…”