Effects of temperature and strain rate on compressive flow behavior of aluminum-boron carbide composites

Abstract

Flow properties of aluminum and aluminum-boron carbide (Al-B4C) composites, containing 5, 10 and 15 wt% B4C, were investigated by compression tests at strain rates of 10−4, 10−3 and 10−2 s−1 over the temperature range 25 to 500℃. The nature of stress–strain curves as a function of reinforcement, temperature and strain rate revealed that (1) flow stress initially increases as the reinforcement increases, but it decreases for Al-15% B4C composite, (2) flow stress increases with the increase in strain rate, with the strain rate sensitivity index varying from 0.01 for aluminum at 200℃ to 0.30 for Al-5% B4C composite. The activation energy for deformation is found to vary from 124 to 187 kJ/mol for Al-15% B4C and Al-5% B4C composites, respectively.

Microstructure evolution of 15 wt% boron carbide/aluminum composites during liquid-stirring process

“…Boron carbide, known for its high hardness (9.5þ in Mohs scale), low density (2.52 g/cm 3 ), good thermal stability (melting point 2427 C), high chemical, and wear resistance, is a promising covalently bonded ceramic material used as reinforcement in Al matrix. [1][2][3] In recent years, B 4 C/Al composites have been widely applied in the nuclear industry due to the high ability of B 10 to capture neutrons (3850 barns). 4,5 B 4 C/Al composite of 15 wt% is one of the neutron absorber materials used for spent fuel storage and transportation application.…”