Elevated-temperature mechanical properties of silicon-carbide-whisker-reinforced aluminum matrix composites

• Published in: Materials science & engineering. A, Structural materials : properties, microstructure and processing Structural materials : properties, microstructure and processing, 1991-10, Vol.144 (1), p.319-326
• Main Authors: Bhagat, Ram B., House, Michael B.
• Format: Article
• Language: English
• Subjects: Applied sciences; Exact sciences and technology; Mechanical properties and methods of testing. Rheology. Fracture mechanics. Tribology; Metals. Metallurgy; Other mechanical properties
• ISSN: 0921-5093; 1873-4936
• DOI: 10.1016/0921-5093(91)90239-J

The aging characteristics, elevated-temperature strength and stiffness as well as creep deformation of aluminum alloy 6061 composites reinforced with silicon carbide (SiC) whiskers ( V f=0.20) have been studied. The peak hardness for this composite was 148 kgf mm −2 after aging for 18 h at 150 °C and 138 kgf mm −2 after aging for 1 h at 200 °C following solutionization for 15 min at 530 °C. The maximum tensile strength was retained after aging for 18–55 h at 150 °C, an improvement of 40% over that of wrought aluminum. The tensile strength of the received composite decreases from 578 MPa at room temperature to 229 MPa at 350 °C. In terms of the use temperature, the composite provides an advantage of approximately 200 °C over that of wrought aluminum. Young's modulus for the composite remains almost constant (104 GPa) from 150 to 350 °C, and it is 58% higher than that of the wrought aluminum at 150 °C. Experimentally determined values of the steady state creep rate range from 4.9 × 10 −9 to 1.3 × 10 −6 s −1 for the composite which shows substantial resistance to creep deformation with respect to the wrought aluminum alloy. The activation energy and stress exponent for the composite are reported and discussed.