铝合金PLC效应与声发射特性的实验研究

Considering the influence of annealing temperature and strain rate on the mechanical properties of 6063 aluminum alloy, the PLC effect and acoustic emission characteristics of aluminum alloy were experimentally studied by material testing machine and acoustic emission testing system. The stress-strain curves of materials under different strain rates and the variation of acoustic emission parameters at different annealing temperatures were obtained. The results show that the stress-strain curves of 6063 aluminum alloy exhibit obvious PLC phenomenon when loaded at strain rates of 2×10^-3, 2×10^-4 and 2×10^-5 s^-1. When the strain rate is reduced, the PLC phenomenon is enhanced, and the conversion from type A to type C occurs. The critical strain of the PLC effect decreases with the increasing annealing temperature at 2×10^-4 s^-1. With the increase of the dynamic dislocation density on the mesostructure, the acoustic emission ringing count increases sharply and reaches the peak value in the yield stage. The acoustic emission activity is weakened in the plastic hardening stage. The burst type signal is generated in the elastic stage and the plastic strengthening stage, while the continuous signal is generated in the yield stage, which is related to the uniform deformation of the specimen and the formation and propagation of the shear deformation zone.