挤压铸造工艺对Al-7Si-0.4Mg-0.3Er汽车左支架组织与性能影响

Effect of squeeze casting process on the microstructure and properties of Al-7Si-0.4Mg-0.3Er alloy bracket for the entransport of automotive engine

摘要:

利用OM、SEM微观组织分析以及显微硬度测试研究了挤压铸造成形工艺对Al-7Si-0.4Mg-0.3Er铝合金汽车发动机左支架显微组织和性能的影响。研究结果表明：凝固顺序对铸件不同部位微观组织影响较大,较先凝固左支架薄壁区初生α-Al组织相较于后凝固厚壁区细小。低温浇注成形相较于高温浇注制备左支架初生α-Al更为细小且均匀分布,但低温浇注支架晶间Er-π-AlFeMgSi 相粗大且偏聚分布。高挤压速度相较于低速制备左支架晶间Er-π-AlFeMgSi 相更为均匀细小。低温650℃高速成形铸件热处理后显微硬度为119HV,标准偏差为5HV,相较于低温低速制备左支架14HV性能分布均匀。铝合金发动机支架适于在低温浇铸高速挤压铸造成形。

Abstract:

An investigation was carried out to study the effect of squeeze casting process on the microstructure and properties of Al-7Si-0.4Mg-0.3Er alloy by OM, SEM and microhardness. The results show that the solidification sequence has great influence on the microstructure of different parts of bracket, the size of primary α-Al grains in the thick parts is smaller than the thin parts. The primary α-Al phase and Er-π-AlFeMgSi phase in bracket is smaller and more uniform distribution, which is fabricated by lower temperature of 650℃ and higher speed 2. The microhardness is 119HV and standard deviation is 5HV after heat treatment, the properties is more uniform distribution than the bracket fabricated by low temperature and high speed. Al-Si alloy engine bracket is suitable for low temperature pouring and high speed forming.