A rapid aging treatment method of Al-7Si-0.55Mg alloy using electric pulse, namely electric pulse aging treatment, is explored in this study. The effect of electric pulse assisted aging on microstructure and properties of Al-7Si-0.55Mg alloy are investigated by means of optical microscopy (OM), scanning electron microscopy (SEM), transmission electron microscopy (TEM), tensile tests and hardness tests. The results show that the microstructure of the Al-7Si-0.55Mg alloy is effectively refined, and the morphology of eutectic Si changes from long and thin strip to a spherical shape or short rod. The elongation of the Al-7Si-0.55Mg alloy is significantly improved after electric pulse assisted aging, albeit it did slightly compromise the tensile strength. It is important to reduce the aging time by 3 h, saving energy. According to classical nucleation theory, the formula of the phase nucleation rate promoted by an electric pulse was determined. The application of an electric pulse can accelerate the nucleation of phase transformation by decreasing the thermodynamic energy barrier, which increases the nucleation rate and significantly improves the properties of the alloy. It provides an experimental and theoretical basis for the Al-7Si-0.55Mg alloy to obtain good mechanical properties and industrial applications.

A wavelet-based signal processing algorithm for airplane cable fault location is proposed in this paper. A Mallet orthogonal discrete wavelet decomposition and reconstruction algorithm is used to eliminate the noise in the aircraft cable fault signal. The experiment result has shown that the character of emission pulse and reflect pulse used to test the aircraft cable fault point are reserved and the high-frequency noise are eliminated by means of the proposed algorithm in this paper.