Effect of hot extrusion on the microstructure of a particulate reinforced magnesium matrix composite

• Published in: Materials science & engineering. A, Structural materials : properties, microstructure and processing Vol. 465; no. 1; pp. 78 - 84
• Main Authors: Wang, X.J., Wu, K., Zhang, H.F., Huang, W.X., Chang, H., Gan, W.M., Zheng, M.Y., Peng, D.L.
• Format: Journal Article
• Language: English
• Published: Amsterdam Elsevier B.V 15.09.2007; Elsevier
• Subjects: Applied sciences; Cold working, work hardening; annealing, quenching, tempering, recovery, and recrystallization; textures; Cross-disciplinary physics: materials science; rheology; Dispersion hardening metals; Dynamic recrystallization; Exact sciences and technology; Extrusion; Fractures; Magnesium matrix composite; Materials science; Mechanical properties and methods of testing. Rheology. Fracture mechanics. Tribology; Metals. Metallurgy; Particle fracture; Physics; Powder metallurgy. Composite materials; Production techniques; PSN; Stir casting; Treatment of materials and its effects on microstructure and properties; Extrusion; PSN; Magnesium matrix composite; Dynamic recrystallization; Particle fracture; Stir casting; Scanning electron microscopy; Metal matrix composite; Segregation; Particle motion; Rupture; Dynamical recrystallization; Composite material; Dispersion strengthened metal; Casting; Optical microscopy; Transmission electron microscopy; Magnesium alloy; Microstructure; Damaging
• ISSN: 0921-5093; 1873-4936
• DOI: 10.1016/j.msea.2007.03.077

A particulate reinforced magnesium matrix composite fabricated by stir casting was extruded at 250 °C with an extrusion ratio of 12:1 and constant RAM speed of 15 mm/s. Extrusion of the composite causes large scale dynamic recrystallization resulting in a fine matrix microstructure. The reinforcing particles stimulate dynamic recrystallization, and dynamic recrystallization in the composite is sensitive to the particle content on a local scale. The particle distribution of the composite before and after extrusion was studied using a window technique. It is found that the segregation of particles in the as-cast composite is largely eliminated by extrusion and the particle distribution is significantly improved. Extrusion-induced damage to the reinforcement is observed in the extruded composites, and the particle fracture induced by extrusion is also sensitive to the particle content on a local scale.