Creep rupture life prediction of short fiber-reinforced metal matrix composites

• Published in: Metallurgical and materials transactions. A, Physical metallurgy and materials science Physical metallurgy and materials science, 1998-07, Vol.29 (7), p.1983-1989
• Main Authors: NAM, H. W, HAN, K. S
• Format: Article
• Language: English
• Subjects: Activation energy; Aluminum base alloys; Aluminum matrix composites; Aluminum oxide; Condensed matter: structure, mechanical and thermal properties; Creep; Creep life; Creep rate; Exact sciences and technology; Fiber composites; Fiber reinforced metals; Fracture surfaces; Heat treating; High temperature; Life prediction; Mechanical and acoustical properties of condensed matter; Mechanical properties of solids; Metal matrix composites; Physics; Rupture; Short fibers; Steady state creep; Strain; Tensile strength; Tensile tests
• ISSN: 1073-5623; 1543-1940
• DOI: 10.1007/s11661-998-0024-2

The creep rupture life of an Al/Al2O3 composite and its creep behavior were studied. The metal matrix composite was produced by using a squeeze casting technique. High-temperature tensile tests and creep experiments were conducted on a 15 vol pct alumina fiber-reinforced AC2B Al alloy metal matrix composite (MMC). The high-temperature tensile strength of Al/Al2O3 composite is 14 pct higher than that of an AC2B Al alloy. The steady-state creep rate and the creep life were measured. The stress exponent in Norton’s equation and the activation energy were computed. The stress exponents of the AC2B and Al/Al2O3 composites were found to be 4 and 12.3, respectively. The activation energy of the AC2B and Al/Al2O3 composites was found to be 242.74 and 465.35 kJ/mol, respectively. A new equation for predicting creep life was established, which was based on the conservation of the creep strain energy. The theoretical predictions were compared with those of the experiment results, and a good agreement was obtained. It was found that the creep life is inversely proportional to the (n + 1)th power of the applied stress and strain failure energy of creep is conserved. The creep fracture surface, examined by scanning electron microscopy (SEM), showed that the MMC specimen failed in a brittle manner.