Influence of solid-solution treatment on corrosion performance of cast AM50 magnesium alloy
It was investigated by quenching the AM50 magnesium alloy test samples in water after T4 treating (420 °C) for 24 h. Then both kinds of the test bars were immersed in 3.5 wt. % NaCl saturation Mg (OH) 2 aqueous solution for 0, 24 and 72 h. Then tensile tests were taken. The microstructure of the samples was analyzed by scanning electronic microscope and X-ray diffraction. The results show that though solid-solution treatment improved the corrosion residual strength of the cast AM50 magnesium alloy for 24h, the deeper corrosion pits developed on the heat-treatment samples on 72h caused more drop of the strength compare to the untreated samples. The solid-solution treatment and the extreme depth theoretical of corrosion pits effect together to the corrosion residual strength.
Research Progress of New Magnesium Alloy
The status quo and development trend of high strength and toughness of magnesium alloy and heat-resistant magnesium alloy are summaized.On the basis of original brands adding trace alloy elements to improve its performance model of gradually turn into the development of new alloys,and abundant use of Gd,Y,Nd,and other RE elements to strengthen alloy model.The existing problems for RE alloying are discussed and the development of magnesium alloys is predicted.
Review of Literature on Probability of Detection for Magnetic Particle Nondestructive Testing
Abstract : A critical review of the available literature concerning the minimum reliably detectable defect size aNDI for magnetic particle testing (MPT) in aerospace applications is presented. Four probability of detection (POD) studies relevant to detection of fatigue cracks in aircraft components were found over the period 1968 to 2011. As the statistical methods used in these four previous studies were either outdated or otherwise deficient, the original data were reanalysed using currently accepted techniques. A meta-analysis of the results is presented, with emphasis on statistical inferences for the defect size expected to be detected with 90% POD. It is shown that the minimum reliably detectable defect size aNDI = 2.0 mm currently specified by the Royal Australian Air Force for wet fluorescent magnetic particle inspection using the continuous method is consistent with estimates of the average performance of MPT derived from the reanalysis of the literature.