Study of Deformation and Destruction Mechanisms of Fibrous Composite Materials by Acoustic Emission Method
摘要
The mechanisms of deformation and destruction of the metallic fiber composite material “aluminum-steel” with different volume fractions of fibers and different structural states of the interphase boundary under static tension conditions were studied using the acoustic emission method. The AMG-6 alloy was used as the matrix of the aluminum-steel composite material, and the reinforcing fibers were stainless austenitic-martensitic steel EP322 wire with a diameter of 350 μm. Samples of matrix and composite material with different volume fractions of fibers, including samples with an intermetallic layer at the fiber-matrix boundary with a thickness of 20 μm, which was formed during annealing at a temperature of 470°C, have been investigated in the work. The samples were tested for static tension at room temperature with a strain rate of 2.8 × 10–3 s–1 using a low-noise 10-ton Instron 3382 mechanical machine with simultaneous recording of a set of acoustic emission signal parameters in the frequency range of 20–1000 kHz and a dynamic range of 84 dB using the SDS1008 diagnostic system. It is found that the amplitude and energy characteristics of acoustic emission signals recorded during static stretching of composite material samples make it possible to control the kinetics of plastic deformation processes, strain hardening of the matrix material, destruction of the intermetallic compound at the interface, and the dynamics of fiber destruction. The possibility of identifying deformation mechanisms based on the analysis of spectral characteristics of acoustic emission signals during static stretching at the stages of yield, strain hardening, plastic flow and fracture of aluminum-steel composite material samples, as well as assessing the degree of influence of the structural state of the matrix-fiber interphase boundary on the nature of fiber fracture has been demonstrated in the work.