Study on Microstructure and Mechanical Properties of TC4/AZ31 Magnesium Matrix Nanocomposites

Abstract

In the field of metal matrix composites, it is a great challenge to improve the strength and elongation of magnesium matrix composites simultaneously. In this work, xTC4/AZ31 (x = 0.5, 1, 1.5 wt.%) composites were fabricated by spark plasma sintering (SPS) followed by hot extrusion. Scanning electron microscopy (SEM) showed that nano-TC4 (Ti-6Al-4V) was well dispersed in the AZ31 matrix. We studied the microstructure evolution and tensile properties of the composites, and analyzed the strengthening mechanism of nano-TC4 on magnesium matrix composites. The results showed that magnesium matrix composites with 1 wt.%TC4 had good comprehensive properties; compared with the AZ31 matrix, the yield strength (YS) was increased by 20.4%, from 162 MPa to 195 MPa; the ultimate tensile strength (UTS) was increased by 11.7%, from 274 MPa to 306 MPa, and the failure strain (FS) was increased by 21.1%, from 7.6% to 9.2%. The improvement in strength was mainly due to grain refinement and good interfacial bonding between nano-TC4 and the Mg matrix. The increase in elongation was the result of grain refinement and a weakened texture.

Solid-State Synthesis of SiC Particle-Reinforced AZ91D Composites: Microstructure and Reinforcement Mechanisms

“…Room-temperature tensile tests were conducted on an E44.304 electromechanical universal testing machine at a velocity of 1 mm/min. In order to ensure the accuracy of the tensile data, each sample was tested three times and the average tensile data for each set of experiments were obtained under the same conditions [46].…”

“…Figure 8 shows the tensile fracture morphology of the SiCp/AZ91D composites. AZ91D alloys are more susceptible to brittle fracture under tensile loading due to their densely arranged hexagonal (HCP) crystal structure, which results in a limited slip system [46,59]. The tensile fracture of the SiCp/AZ91D composite shown in Figure 8b-d,f is a disintegrated fracture with more dimples (purple arrows) [60], tearing ridges (green arrows) Figure 8 shows the tensile fracture morphology of the SiCp/AZ91D composites.…”

“…The tensile fracture of the SiCp/AZ91D composite shown in Figure 8b-d,f is a disintegrated fracture with more dimples (purple arrows) [60], tearing ridges (green arrows) Figure 8 shows the tensile fracture morphology of the SiCp/AZ91D composites. AZ91D alloys are more susceptible to brittle fracture under tensile loading due to their densely arranged hexagonal (HCP) crystal structure, which results in a limited slip system [46,59]. The tensile fracture of the SiCp/AZ91D composite shown in Figure 8b-d,f is a disintegrated fracture with more dimples (purple arrows) [60], tearing ridges (green arrows) [61], cleavage planes (red arrows) [62], and cracks (yellow curves) [63] on the fracture.…”

“…At low SiCp content, the fracture of SiCp/AZ91D composites mainly occurs in the matrix. The fracture mechanism of SiCp/AZ91D composites is still dominated by brittle fracture due to the poor toughness of magnesium alloys, which have HCP structures [46]. However, when the reinforcing phase content is too high, the continuity of the matrix is disrupted.…”

Effect of Nano-Ti Particles on Microstructure and Mechanical Properties of Mg-3Al-1Zn Matrix Composites

“…In general, for powder metallurgy and stirred casting, the reinforcement has better dispersion in the composites prepared by powder metallurgy method [ 51 , 52 ]. However, the density of composites prepared by conventional powder metallurgy may have certain defects [ 53 ], and hot extrusion can improve this defect [ 54 ].…”