Impression creep behavior of extruded Mg–SiCp composites

• Published in: Materials science & engineering. A, Structural materials : properties, microstructure and processing Vol. 640; pp. 91 - 97
• Main Authors: Labib, F., Mahmudi, R., Ghasemi, H.M.
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 29-07-2015
• Subjects: Creep (materials); Creep mechanism; Diffusion; Extrusion; Impression creep; Magnesium; Mg–SiCp composite; Particulate composites; Silicon carbide; Stresses; Impression creep; Creep mechanism; Mg–SiCp composite
• ISSN: 0921-5093; 1873-4936
• DOI: 10.1016/j.msea.2015.05.090

Impression creep experiments were performed on pure magnesium and its composites reinforced with 5, 7.5, 10 and 15vol% of 10-μm SiCp fabricated by powder metallurgy and extrusion processes. Tests were conducted on planes perpendicular to the extrusion direction, in the temperature range 423–473K and under stress level in the range 150–250MPa. Analysis of data showed that for all loads and temperatures magnesium reinforced with 10vol% SiCp had the lowest creep rates, and thus, the highest creep resistance among all materials tested. The improved properties of the composite materials were discussed based on various strengthening mechanisms. The stress exponents of 7.0–7.9 and activation energies of about 90kJmol–1, which are close to that for dislocation-pipe diffusion in Mg, were almost the same for all tested materials. These creep parameters imply that the dominant creep mechanism could be dislocation climb controlled by pipe diffusion.