Properties of squeeze cast Mg-10Al-Mn alloy and its alumina short fibre composites

Magnesium alloys are very suitable for applications that require materials with high strength-to-weight ratio. However, the use of magnesium alloys is limited due to their low elevated temperature properties. Magnesium matrix composites are the possible alternatives. The present work involved the production and subsequent property evaluation of AM100 magnesium alloy and its alumina short fibre reinforced composites. Studies on microstructure, hardness, density, stiffness, tensile properties, impact strength, wear resistance and corrosion resistance were carried out. Results indicate the significant improvement in the properties achieved by making composites. The findings also highlight the dominant roles of the base alloy matrix and the fibre volume fraction in determining the above properties

The tensile behavior of two magnesium alloys reinforced with silicon carbide particulates

In this paper is reported the results of a study aimed at establishing an understanding the role of particulate reinforcement on tensile deformation and fracture behavior of magnesium alloys discontinuously-reinforced with silicon carbide (SiC) particulates. An increase in particulate reinforcement content was observed to decrease ultimate tensile strength and ductility of the composite when compared to the unreinforced counterpart. Cracking of the individual and clusters of reinforcing particulates present in the microstructure dominated tensile fracture of the composite, on a microscopic scale. Final fracture occurred as a result of crack propagation through the matrix between particulate clusters. The fracture behavior of the composite is discussed in light of the concurrent and mutually interactive influences of intrinsic microstructural effects, deformation characteristics of the metal matrix and the particulate reinforcement, nature of loading and local stress state

The tensile behavior of two magnesium alloys reinforced with silicon carbide particulates

In this paper is reported the results of a study aimed at establishing an understanding the role of particulate reinforcement on tensile deformation and fracture behavior of magnesium alloys discontinuously-reinforced with silicon carbide (SiC) particulates. An increase in particulate reinforcement content was observed to decrease ultimate tensile strength and ductility of the composite when compared to the unreinforced counterpart. Cracking of the individual and clusters of reinforcing particulates present in the microstructure dominated tensile fracture of the composite, on a microscopic scale. Final fracture occurred as a result of crack propagation through the matrix between particulate clusters. The fracture behavior of the composite is discussed in light of the concurrent and mutually interactive influences of intrinsic microstructural effects, deformation characteristics of the metal matrix and the particulate reinforcement, nature of loading and local stress state

Tensile strength and fracture toughness of two magnesium metal matrix composites

Tensile strength and fracture toughness of two magnesium metal matrix composite

Influence of processing and reinforcement on microstructure and impact behavior of magnesium alloy AM100

Reinforcing magnesium alloys with a discontinuously dispersed ceramic phase has engineered a new family of materials that are marketed under the trade name "metal-matrix composites". Continuous research efforts in the processing of these materials have provided the necessary impetus for their emergence and use in structural, automotive and even aerospace-related components. In this paper we report the results of a study aimed at understanding the role of short-fiber reinforcements (discontinuously dispersed through the metal-matrix of magnesium alloy AM100) on impact deformation and fracture behavior. In particular, the role of volume fraction of the reinforcing phase on impact energy and fracture behavior is presented and discussed. An increase in short-fiber reinforcement content in the magnesium alloy metal-matrix is obsd. to have a detrimental influence on impact energy when compared to the unreinforced counterpart. Micro cracking in the metal-matrix coupled with failure of the reinforcing fibers, both independently dispersed and in clusters, dominates the fracture sequence at the microscopic level. The final fracture behavior of the composite material is discussed in the light of the concurrent and mutually interactive influences of nature of loading, local stress state, intrinsic microstructural effects and deformation characteristics of the composite constituents

Influence of Reinforcement and Processing on the Wear Response of Two Magnesium Alloys

Reinforcement of magnesium alloys with ceramic particulates has engineered a new family of materials that are marketed under the trade name metal-matrix composites. Rapid strides in the processing of these materials during the last two decades have provided the necessary impetus for their emergence and use in structure and automotive-related components. In this paper are reported the results of a study aimed at understanding the role of the reinforcing phase on the wear behavior of two magnesium alloys discontinuously reinforced with silicon carbide (SiC) particulates and saffil alumina short fibers. The wear rate of the reinforced magnesium alloy metal matrices is lower than that of the unreinforced counterpart (AM60-T5 and AZ92-T6). The improved wear resistance of the composite microstructures is attributed to the presence and distribution of the ceramic reinforcement phase, which minimizes the tendency for material flow or plasticity at the surface during sliding. Wear rate is influenced by sliding speed, nature, and volume fraction of the reinforcing phase. For the unreinforced magnesium alloys, an increase in sliding speed results in a marginal increase in wear rate. For a given reinforcement (particulate and saffil fiber) in the magnesium alloy metal matrix, an increase in sliding speed had a negligible influence on wear rate. An increase in volume fraction of the reinforcing phase in the magnesium alloy metal matrix resulted in a noticeable drop in wear rate. Coefficient of friction of the unreinforced magnesium alloys AM60 and AZ92 decreased with an increase in sliding speed regardless of the amount of applied load. Addition of reinforcement, i.e., particulates and short fibers, to the magnesium alloy metal matrix resulted in a significant drop in coefficient of friction. However, increase in volume fraction of the reinforcing base in the magnesium alloy metal matrix had negligible influence on coefficient of friction. The wear characteristics of the reinforced metal matrix are discussed in light of the mutually interactive influences of intrinsic microstructural effects, strength of the microstructure, sliding speed, and local stress state