电磁/超声复合场作用下非晶合金板材连铸技术基础研究

In this project, taking copper-based amorphous alloy as the research object, micro-alloying compositions are designed to improve the glass-forming ability (GFA). Amorphous sheet preparation by electromagnetic / ultrasonic composite continuous casting method was put forward based on the patented technology with independent intellectual property rights, that is graphite and water-cooled copper composite molding under different pressure double-chamber. The coupling effect of electromagnetic field and ultrasonic field was innovatively taken advantage of in the continuous casting process: when imposing power ultrasound, gas and inclusions could be removed from the melt because of the ultrasonic cavatition function so that the heterogeneous nucleation was suppressed and the melt would be purified; when imposing electromagnetic field on the front of the graphite mold, the purification function of the electromagnetic force could not only raise the GFA by reducing the impurities involved in the cause of heterogeneous nucleation, but also amplify the effects of the ultrasound. Because of the induction heat generating by electromagnetic field on the graphite mold and its internal melt, the melt that flowed into the water-cooled copper mold would have a certain degree of superheat before molding and cooling, which was conducive to satisfy the glass forming criteria of the cooling speed and the temperature gradient and to realize rapid solidification. Amorphous sheets can be superplastic formed into various key precision devices, what's more, it has important academic value and practical significance in raising the level of China's aviation, aerospace, military industry, precision machinery, microelectronics, communications, biomedical and many other high-tech fields.

本项目以铜基非晶合金为研究对象，以提高非晶形成能为目标进行微合金化成分设计；在具有自主知识产权的专利技术，即双室差压石墨/水冷铜模复合铸型基础上，提出电磁/超声复合连铸法制备非晶合金板材；创新性的利用电磁场/超声场耦合效应，在连铸过程中施加功率超声，利用超声波的空化作用去除非晶合金熔体中的气体和夹杂，提高熔体纯净度、消除熔体中的团簇，从而抑制异质形核；在石墨铸型前端施加电磁场，既发挥电磁力的净化作用减轻杂质卷入引起的异质形核，提高合金非晶形成能力的同时，又可扩大超声的作用范围；而电磁场对石墨铸型及其内部非晶合金熔体的感应加热作用，可使熔体以一定的过热度进入水冷铜模中成型、冷却，更有利于满足非晶形成的冷却速度和温度梯度条件，实现快速凝固。非晶板材经超塑成型可制备成各种关键精密器件，对提升我国航空、航天、军工、精密机械、微电子、通讯和生物医学等高技术领域的水平具有重要学术价值和现实意义。

本项目名称为电磁/超声复合场作用下非晶合金板材连铸技术基础研究，在项目执行期间按照申报内容和目标开展研究工作，按计划完成项目研究内容，并取得良好预期进展和成果。.新型铜基块体非晶合金成分以Cu-Zr-Al三元合金为基础，设计Cu40Zr50Al10 、Cu47Zr45Al8、Cu50Zr42Al8三种非晶合金，其形成能分别为18、15和11mm。通过对(Cu47Zr45Al8)100-xREx系合金热力学参数、临界尺寸和力学性能的分析，优化设计出具有大形成能、低成本的新型铜基非晶合金成分(Cu47Zr45Al8)98.5Y1.5；.设计出新型真空电磁、超声复合水平连铸装置，由双腔室、真空系统、熔炼系统、拉坯系统构成。熔炼、浇注及电磁及超声作用在第一腔室完成，连铸过程中两个腔室联通并保持等压差。压差既有效提高金属液充型能力，也改善连铸板材表面质量。在苏州州盛非晶科技有限公司实现技术转让。.开展超声波对非晶形成能力影响机理研究：超声波作用于非晶、铜合金和球铁，分析功率超声抑制异质形核、控制晶体相生长，提高非晶形成能力和改善组织性能的影响；.电磁场对非晶形成作用机理研究结果表明，电磁场有效提高非晶熔体的充型能力，电磁压力改善铸坯与结晶器的接触压力，同时净化熔体，减轻非晶合金表面的异质形核，使连铸坯表面具有良好的金属光泽。掌握了电磁场施加方法和关键电磁参数；提出外场的选择及工艺设计依据；.建立非晶合金板材连铸过程数学模型，分析拉速、冷却强度、拉坯模式和流道结构等对冷却速度和凝固过程的影响，对结晶器和工艺参数的优化提供指导；.进行大量的非晶合金板材连铸试验，探讨有无电磁场、超声作用下的板材连铸，优化工艺参数和结晶器结构，制备出截面尺寸50mm×6mm×400mm新型铜基非晶合金板材； .分析连铸非晶合金板材的微观结构、热稳定性、力学、生物相容性及耐腐蚀、耐磨损等性能等，进行超塑成形试验。非晶合金具有良好耐磨性、生物相容性和超塑成形性。.聘请美国学者米斯拉教授为海天学者特聘教授，参加国际国内会议6次，将于2018年1月20日在深圳举行的中国非晶合金论坛做大会特邀报告。发表论文22篇，获批发明专利9项，实用新型专利1项，申报发明专利8项，培养博士、硕士研究生12名，博士后2名。