The effects of heat treatments, including T4, T5, T6 treatments, on corrosion behaviors of Mg-7Al-2Sn (AT72) alloy processed by high vacuum die casting have been investigated. The optical microscope, scanning electron microscope observations were used to analyze the microstructures, especially the distribution of second phase, phase contents and grain size. The hydrogen evolution tests, electrochemical methods including open circuit potential curves and polarization curves were used to describe the corrosion properties as well. The results indicated that different heat treatments had influence on microstructures, especially distribution of second phase, phase contents and grain sizes. The existence of second phase had a relationship with corrosion properties, in which the as-cast samples showed low corrosion rate in hydrogen evolution tests while the heat treatment methods had little impact on improving corrosion resistance. The electrochemical analyses also agreed with this observation. Based on these results, the optimized heat treatment method for corrosion resistant AT72 magnesium alloy has been established.

The manufacturing engineering of bamboo fiber reinforced friction material was introduced in this paper. ANSYS was used to do adaptive meshing and establish the contact, impose constraints load and solve, then the temperature field of bamboo fiber reinforced friction material was obtained. The results showed that under the coupling effect of friction heat and pressure, Brake blocks and brake discs in the contact area showed local changes in temperature and stress characteristics. The thermal stress of coupled parts contact surface showed a inhomogeneous distribution. Contact pressure distribution and temperature distribution interact each other, the contact pressure distribution of the coupled parts affects the temperature distribution, and the local feature of temperature distribution of the coupled parts conversely affects the contact pressure distribution. It will provide an important theoretical basis for devising friction brake and selecting material of the friction pair.