挤压铸造制备铜铝双金属复合材料固液复合机理研究

Put the copper insert which is sprayed with zinc into the die cavity, then aluminum or its alloys is cast around it and solidified under applied pressure, thus Cu/Al bimetal composites can be fabricated by squeeze casting method. In order to realize metallurgical bonding between solid Cu and liquid Al and obtain Cu/Al bimetal composites with excellent mechanical, thermal and electrical properties, thermal spray zinc method will be introduced to protect the surface of the solid copper insert from oxidation, processing parameters will be optimized to control the composition and thickness of the Cu/Al intermetallic compounds. We will study the effect of zinc coating thickness, squeeze casting and heat treatment parameters on the diffusion behavior and distribution of elements Cu and Al, the composition and distribution of intermetallic compounds, the growth behavior and thickness of interface layer, microstructure, fusion, solidification and migration of the interface region. We will evaluate the bonding strength, thermal and electrical properties of the Cu/Al bimetal; establish relationship among zinc coating thickness and squeeze casting parameters, microstructure, mechanical property and thermal and electrical properties; illustrate the diffusion behavior of element Cu and Al in the interface region; reveal the formation sequence and growing law of the intermetallic compounds; clarify the bonding mechanisms between solid Cu and liquid Al by squeeze casting method; obtain the technological prototype of Cu-Al bimetal fabricated be squeeze casting. The project aims at establishing the processing fundaments of squeeze casting fabricating Cu-Al bimetal, inaugurating new technology routes to develop Cu-Al bimetal with excellent properties and providing technical support to its industrialization and widely application.

将纯铜表面喷镀锌后置于型腔内，浇注铝或铝合金液，挤压铸造制备铜铝双金属复合材料；通过喷镀锌防止氧化、挤压铸造及后续热处理工艺参数优化，控制界面组织结构及厚度，实现固态铜和液态铝的良好冶金结合，获得具有优良力学性能及导电、导热性能的铜铝双金属复合材料。研究挤压铸造和加压扩散偶实验时喷镀锌层厚度、挤压铸造、热处理工艺参数对铜铝双金属复合材料元素扩散及分布、界面化合物形成及分布、组织结构、界面厚度、界面结合的影响规律；弄清界面处的熔合和凝固行为、固/液界面迁移行为；揭示挤压铸造铜铝双金属复合材料的固液复合机理；评价铜铝双金属复合材料的结合强度、导电和导热等性能，建立喷镀锌层厚度、工艺参数与界面组织结构、力学性能、导电和导热性能之间的关系；获得挤压铸造制备铜铝双金属复合材料的技术原型。本项目将奠定挤压铸造制备铜铝双金属复合材料的技术基础，为铜铝双金属复合材料的制备和生产开辟新途径和提供技术支撑。

双（多）金属复合材料是采用一定的复合工艺将两种或多种物理、化学、力学等性能不同的基体金属在界面上实现牢固的冶金结合而制备的一种新型复合材料。铜/铝双（多）金属复合材料作为一种常见的双（多）金属复合材料，广泛应用于汽车、电力、热传输、通讯、装饰等领域。本文采用固液复合砂型重力铸造和金属型重力铸造分别制备了两种不同的铜/铝双金属复合材料，系统研究了冷却速率和浇注温度对铜/铝双金属复合材料界面组织和力学性能的影响规律，并对界面金属间化合物进行表征、鉴定，分析了不同界面组织结构的形成原因，建立了界面组织与力学性能之间的关系，完善了铜/铝双金属复合材料固液复合机理研究。针对实际生产中单一固液铸轧工艺无法制备低铜厚度比（铜层厚度比<8%）的铜/铝复合材料的问题，采用“铸轧+轧制”联合复合工艺制备了低铜厚度比Cu/8011/1060（铜层厚度比为4.1%）和Cu/8011/5052（铜层厚度比为1.7%）多金属复合材料，系统研究了轧制压下率和热处理温度对多金属复合材料显微组织演变与力学性能的影响规律。通过在6101预置材料表面电镀Zn处理后重力铸造及挤压铸造的方法，成功制备了固液复合6101/A356、6101/6101及6101/纯铝等体系双金属复合材料，研究了其组织结构和力学性能，探明了工艺参数的影响规律。在前述研究基础上，利用获得的技术原型，通过挤压铸造制备铝/铝和铜/铝双金属电动汽车驱动电机转子。