(1. 北京科技大學(xué) 材料先進(jìn)制備技術(shù)教育部重點(diǎn)實(shí)驗(yàn)室，北京 100083；
2. 北京科技大學(xué) 新材料技術(shù)研究院，北京 100083)
摘 要: 采用水平連鑄直接復(fù)合成形工藝，制備斷面尺寸為50 mm×30 mm、銅包覆層厚度為3 mm的銅包鋁復(fù)合棒材，并分別采用拉剪試驗(yàn)、XRD、SEM、EDS和EPMA等對(duì)鑄棒界面的結(jié)合強(qiáng)度、形貌和組成進(jìn)行表征。結(jié)果表明：銅包鋁復(fù)合鑄棒界面層的主要組成為CuAl2和Cu9Al4，在近銅側(cè)由平面狀Cu9Al4(Ⅰ區(qū))和CuAl2胞晶(Ⅱ區(qū))兩區(qū)組成；在近鋁側(cè)為α(Al)+CuAl2共晶組織(Ⅲ區(qū))。在鑄棒橫斷面上不同位置的界面層結(jié)構(gòu)相同，但界面總厚度不均勻，上部厚度最大，達(dá)到220 μm，且CuAl2胞晶組織較發(fā)達(dá)；側(cè)部厚度最小，約為110 μm；下部厚度為150 μm。界面層總厚度，特別是Ⅱ區(qū)CuAl2胞晶層厚度對(duì)界面剪切強(qiáng)度有顯著影響，因而橫斷面上部的界面剪切強(qiáng)度較低，為24.7 MPa；側(cè)部和下部的界面剪切強(qiáng)度接近，分別為35.6和33.4 MPa。XRD和斷口分析表明，界面分離發(fā)生在界面層的Ⅰ區(qū)和Ⅱ區(qū)內(nèi)。在后續(xù)軋制加工過(guò)程中，界面層發(fā)生斷裂而破碎，其破碎程度隨變形程度的增加而增加；當(dāng)壓下率達(dá)到67.7%以上時(shí)，形成大量純銅和純鋁直接接觸無(wú)明顯擴(kuò)散的結(jié)合界面，原界面化合物層破碎為尺寸較小的碎片沿界面不連續(xù)分布。
關(guān)鍵字: 銅包鋁復(fù)合材料；矩形斷面；界面；水平連鑄直接復(fù)合
（1. Key Laboratory for Advanced Materials Processing, Ministry of Education,
University of Science and Technology Beijing, Beijing 100083, China;
2. Institute for Advanced Materials and Tech）
Abstract:Copper cladding aluminum (CCA) rods with the section dimensions of 50 mm×30 mm and the sheath thickness of 3 mm were fabricated by horizontal core-filling continuous casting (HCFC) technology, and the bonding strength, micro-morphology and composition distribution of the casting rod interface were characterized by tensile shear test, XRD, SEM, EDS and EPMA. The results show that the primary intermetallic compounds in the interface of the casting composite rod include CuAl2 and Cu9Al4 phase. The interface at the side of Cu is composed of the Cu9Al4 planar layer (zone Ⅰ) and CuAl2 cellular crystal (zone Ⅱ), and that at the Al side is α(Al)+CuAl2 eutectic texture (zone Ⅲ). At different positions of transverse section of the CCA rod, the interface has the same microstructure, but the total thickness of the interface is different. The interface at the top position has the largest thickness of 220 μm, and coarse CuAl2 cellular crystal; that at the side position has the total thickness of 110 μm, and that at the bottom position is 150 μm. The total thickness of the interfacial layer, especially, the CuAl2 cellular crystal, has serious influence on the bonding strength. So, the bonding strength of interface at the top position is the lowest, which is 24.7 MPa, and the bonding strengths at the side and bottom position are approximate, which are 35.6 and 33.4 MPa, respectively. XRD and fractography analyses indicate that the interface is separated in zonesⅠand Ⅱ after the tensile shear test. In the subsequent rolling process, the interfacial layer is fractured and fragmented. The fragmentation degree increases with the deformation degree increasing. When the total reduction is greater than 67.7%, a great deal of Cu/Al direct bonding interface is generated which has no obvious diffusion, and the intermetallic compound which is formed in the casting process distributes discontinuously as micro-fragments along the interface.
Key words: copper cladding aluminum; rectangle section; interface; horizontal core-filling continuous casting
