Effects of low temperature aging on the microstructure and properties of QBe2.0 alloy

The microstructure and properties of QBe2.0 alloy aging at the temperature of 280 ℃ were investigated. The room temperature tensile test, hardness testing and conductivity test were performed to measure the properties of the alloy, while the OM, XRD, TEM and other methods were used to analyze the microstructure. The results showed that with the prolonging of aging time, the hardness, yield strength and tensile strength of the alloy continue to increase, reaching the peak aging state at 8 h. The main strengthening phase was the γ' phase in the matrix in the form of amplitude-modulated structure. Since the lattice distortion was caused by coherent precipitated phase of γ〞, the conductivity of the alloy first decreased and then increased with the aging time. After 16 hours, the alloy reached the over-aged state. It was obvious to find that the discontinuous precipitation widely appeared at grain boundary and small amount of γ phase was detected in XRD pattern. Both two factors deteriorated the mechanical properties of the alloy.