新型高强高导电铜锆铝合金快速凝固连续铸造技术研究

High-strength and high-conductivity copper alloys are a new type of important structural and functional materials in such high-tech fields as microelectronics, communications, transportation and aerospace. Preliminary researches showed that a new Cu-Zr-Al alloys series with high-strength and high-conductivity have been obtained for high density duplex fibrous structure with minor addition of Al by rapid solidification. With the advantage of the rapid solidified technology in improving copper alloy strength and conductivity and the significant roles on melt purification and grain refinement strengthening of microalloying Ce and Y, the researches for revealing the evolution of microstructure and enhanced phases stabilization mechanism of the Cu-Zr-Al alloys under rapid solidification will be studied in this application. The crystalline and strengthening mechanisms of the Cu-Zr-Al alloys will be built to understand the relationship between microstructure and properties. Through the investigation of numerical simulation on temperature field, the critical cooling conditions for the formation of high density duplex fibrous structure in Cu-Zr-Al alloys can be realized. By the development of graphite/water-cooled copper mold continue casting method with high cooling intensity, a new preparation process of high efficiency and stability for the high-strength and high-conductivity material can be obtained, which will make products of high strength and high conductivity copper alloy by rapid solidification no longer limit to ribbon or single ingot. The new ideas and new methods mentioned above will also be beneficial for the development and application of the high-strength and high-conductivity materials in the future.

高强度高导电性铜合金，是微电子、通讯、交通和航空航天等高新技术领域重要的新型功能材料。本申请前期预研中发现：Al元素的添加可以使Cu-Zr合金在快速凝固后，直接获得细密纤维状的双相增强结构，有效地提高了基体合金的强度。鉴于快速凝固技术在提高铜合金强度和导电率方面的优势，以及稀土元素(Ce和Y)对铜合金熔体净化和细晶强化的显著作用，本项目将以Cu-Zr-Al系合金为研究对象，通过稀土元素微合金化和快速凝固技术，揭示合金组织的演变规律及增强相的稳定机制，明确组织结构与综合性能的关系；通过对Cu-Zr-Al系合金凝固温度场的计算分析，获得形成纤维增强结构的冷却条件，优化石墨水冷铜模铸型的结构设计，建立起适用于高强高导电Cu-Zr-Al合金的快速凝固连铸系统，获得新型高效稳定的制备工艺，使快速凝固高强高导电铜合金不再限于薄带或单一块锭产品，为今后我国高强高导电材料的开发和应用提供新思路和新方法。

高强度高导电铜合金，是微电子、通讯、交通和航空航天等高新技术领域重要的新型功能材料。本项目研究了微合金化的CuZrAl合金组织与性能的关系。探索了热处理工艺对合金导电率和力学性能的影响。同时，设计出快速凝固连续铸造结晶器，研究了合金的快速凝固连铸技术，并对连铸合金棒材进行了组织与性能评价。.铜模喷铸2 mm直径Cu90Zr10-xAlx合金棒由α-Cu和Cu5Zr相组成，Al固溶于α-Cu中。其中Cu90Zr9Al1由α-Cu+Cu5Zr的共晶组织基体和其上弥散分布的细小纤维状Cu5Zr增强相组成，Cu90Zr7Al3和Cu90Zr5Al5由先析出的枝晶状α-Cu和枝晶间的α-Cu+Cu5Zr共晶组织构成，Cu90Zr3Al7和Cu90Zr1Al9由α-Cu晶粒和晶界处的少量α-Cu+Cu5Zr共晶组织所构成。Cu90Zr9Al1、Cu90Zr7Al3和Cu90Zr5Al5合金棒的压缩屈服强度分别达到1513、1066和812MPa，维氏硬度分别为420、326和250。.铜模铸造20mm直径的Cu99Zr0.5Al0.5合金由细小的等轴晶粒组成，晶界处存在少量α-Cu+Cu5Zr共晶组织，冷轧后等轴晶粒转变为条带状变形组织，晶界处共晶组织破碎，呈不连续条状分布。经过70%冷轧450℃/1h时效的Cu99Zr0.5Al0.5合金，具有较好的综合性能，抗拉强度为460MPa，伸长率为16%，导电率为60% IACS。对添加0.01%Ce的合金进行950℃/1h固溶处理，固溶处理后经70%冷轧450℃/2h时效处理，抗拉强度达到469.2 MPa、导电率达83.3% IACS。.自主设计出真空双室差压快速凝固水平连铸系统，成功连铸出纯铜和CuZrAl合金及CuZrAlCe合金棒材，合金棒具有良好的表面质量。其中，Cu90Zr9Al1合金棒由交替分布的α-Cu和Cu5Zr相组成，压缩断裂强度为996MPa，抗拉强度为865MPa，导电率为12.3%IACS。对于添加0.01at%Ce的Cu-Zr合金，在1250℃的连铸温度下、使用2mm/s的拉坯速度、拉5s停2s的连铸工艺、2L/min的冷却水流量和0.05MPa压差，成功制备出表面质量良好的合金棒。