新型纳米稀土相在铝硅合金中的形成、演化规律及其强化机制

We had reported the effects of rare earth elements Er, Sm additions on microstructure and mechanical properties of Al-Si aluminum alloys, which had been published in the Journal of Alloys and Compounds in 2012 and 2013. The results shows that the microstructure and mechanical properties of Al-Si alloys were obviously improved with Er or Sm addition, and a lot of nano rare earth particles formed in Al-Si alloys. In order to further understand the role of nano rare earth phases in alloying Al-Si alloy, the nano rare earth phases and Al-Si alloys were studied for this research, and the alloying design method, the high intensity ultrasonic with in-situ synthesis technique and rapid solidification technique will be used to develop the new nano rare earth phase/ Al-Si alloys. In order to obtain new nano rare earth phases / Al-Si alloys and its preparation technology, the present research mainly focus on the formation and evolution laws of nano rare earth phases in Al-Si alloys, the relationship between and among strengthening mechanisms of Al-Si alloys, the dispersion strengthening effect of nano rare earth phases, and rare earth alloying, the technology of in-situ synthesis nano rare earth phases / Al-Si alloys under ultrasonic, etc. The applying of this research achievements will be beneficial in theory research and engineering application for enhancing the comprehensive properties of Al-Si alloys and improving the application level of the Al-Si alloys for Chinese foundry enterprises.

课题组2012、2013年在《Journal of Alloys and Compounds》上发表了关于稀土元素Er、Sm对铝合金的组织和性能的影响规律。研究发现：铝硅合金的组织得到显著细化，机械性能大幅提高，合金中还形成了大量颗粒状纳米稀土相。为了进一步探明纳米稀土相在合金化中的作用，本项目以纳米稀土相和铸造铝硅合金为研究对象，采用合金设计、高能超声原位合成、快速凝固等方法与技术,深入和系统的研究纳米稀土相在铝硅合金中的形成与演化规律、纳米稀土相弥散强化效应与稀土合金化协同作用对铝硅合金机械性能的提高机制、高能超声原位合成纳米稀土相/铝硅合金工艺等关键科学问题与技术，以获得新型纳米稀土相/铝硅合金及其制备工艺。本项目的成功应用将为提高铝硅合金的综合性能和提升铝硅合金在国内铸造企业的应用水平奠定技术基础，具有重要的理论意义和工程应用价值。

铸造铝硅（Al-Si）合金具有优良的流动性好、气密性好等特性，然而合金中粗大的硅（Si）相使得合金的强度和韧性下降，切削加工性能差。稀土元素能将Al-Si合金中Si相由粗大的板片状转变为细小的纤维状或颗粒状，使合金的机械性能大幅提高，合金中还形成了大量颗粒状纳米稀土相。本项目为探明纳米稀土相在合金化中的作用，以纳米稀土相和铸造铝硅合金为研究对象，采用合金设计、高能超声原位合成、快速凝固等方法与技术，深入和系统的研究了纳米稀土相在铝硅合金中的形成与演化规律、纳米稀土相弥散强化效应与稀土合金化协同作用对铝硅合金机械性能的提高机制、高能超声原位合成纳米稀土相/铝硅合金工艺等关键科学问题与技术，获得了新型纳米稀土相/铝硅合金及其制备工艺。新型稀土铝合金的流动性比传统铝合金提高17～27%，热裂倾向性减少11%，室温抗拉强度提高23%，延伸率提高60%。在国家自然基金青年项目三年来的资助下，共发表学术论文8篇，其中国际期刊7篇，中文核心刊物1篇，SCI收录7篇（其中1篇为1区论文），获批国家发明专利8项，相关研究成果所申请获批的国家发明专利经学校同意授权转让给了江西铃格有色金属加工有限公司（省内最大的铝合金压铸企业），实现了产业化对接。