The effects of temperature and strain rate on the properties of carbon-fiber-reinforced 7075 aluminum alloy metal-matrix composite

The mechanical properties and fracture behavior of 7075-T6 aluminum alloy reinforced with 0.15 V-f of laminated carbon fiber were studied for the effects of strain rate between 10(-1) s(-1) and 3.3 x 10(3) s(-1) and temperature between 25 and 300 by using a Saginomiya 100 metal-forming machine and a compressive split-Hopkinson bar. The effects of strain rate and temperature on flow behavior of the composites tested have been evaluated and fractographic observations made of the fracture surfaces in order to understand the fracture mechanisms. Results show that the composite flow stress is sensitive to both strain rate and temperature, and that temperature increase noticeably reduces the strain-rate dependence of the flow stress. Fracture strain is found to be greater at low strain rates, increasing, however, with strain rate and temperature in the dynamic range. Changes of fracture features and damage process appear to relate directly to both strain rate and temperature. Damage initiation and propagation processes are identified, (C) 2000 Elsevier Science Ltd. All rights reserved.