改良劑(鍶、銻)與熱處理對Al-11Si-3Cu-0.5Mg鑄造合金微結構及磨耗性質之影響

Al-Si alloys have an excellent castability, abrasion resistance, specific strength, low thermal expansion coefficient, and thermal conductivity. It can absorb the heat generated by vehicle parts easily during operation. Si- solubility in Al is extremely low (about 1.6 wt%). The Si-particles in the Al-Si alloy are almost in the form of pure Si. The hard and brittle Si-particles are the main factor for the good wear resistance of the alloys. Therefore, in the past ten years, Its casting alloys have been widely used in the automotive industry to replace cast–Fe in engine parts, such as engine blocks and cylinder heads. While the Si content in the reaches the eutectic composition. The resistance is improved because the Si distribution is more uniform than other composition forms (hypoeutectic, hypereutectic). Our leading research of this research found, that improve the morphology of ascast eutectic Si became a layered and fibrous structure. During the solution treatment, the eutectic Si improved by Sr is coarser. However, those improved by Sb become finer. It shows that the solution treatment and the addition of modifiers (Sr, Sb) can control the eutectic Si-morphology and hardness. The cooperative enterprise deeply feels that these results are beneficial to the alloys' wear resistance and has practical value. We also feels it is necessary to discuss its academic theory clearly, so it submits an application for this project. The cooperative company has received a large number orders of automotive cast Al-alloy, especially for 4y32 (Al-11Si-3Cu-0.5Mg). Due to the wear resistance requirements of ASTM G99-175 specification (<0.02mg/m). We hope this research to improve the technology and knowledge of casting, mechanical properties, wear resistance, etc., Academically, it can also provide valuable and correct theoretical references.