Investigation on the mechanical properties and thermal deformation of Be-Al alloy prepared by spherical beryllium powder

Abstract:

A new Be-50 wt. %Al alloys were prepared by spherical beryllium powder. The Be phase keeps near spherical shape in the billet prepared by hot isostatic pressing ,and the proportion of Be phase with shape factor greater than 0.5 exceeds 77%. At room temperature, the alloy has good rigidity and the elastic modulus is 171GPa. The uniaxial compression experiment was carried out on the Gleeble tester to study the hot deformation ability of Be-50Al alloy at the temperature range from 250℃ to 550℃, and the strain rate 0.01s-1.The results show that the peak stress is significantly lower than that of traditional beryllium aluminum alloy. The strain hardening index of Be-50Al alloy is very stable at the temperature of 300℃ ~ 350 ℃, and it has good uniform plastic deformation ability. The deformation mechanism of compressed Be-50Al at various temperatures is mainly dominated by the plastic deformation of aluminum phase well coordinated by the beryllium phase. The tensile fracture surfaces at ambient temperature show cleavage fracture of beryllium particles, ductile fracture of aluminum and the interfacial debonding between beryllium phase and aluminum phase. Differently, the compression fracture at high temperature is caused by tearing of aluminum phase.

Key words:Spherical beryllium powder; Mechanical properties; Compression deformation; Micro-structure