冷軋及退火對銅鋁復合板界面層與性能影響研究
發(fā)布時間:2018-05-06 01:00
本文選題:銅鋁復合板 + 鑄軋復合; 參考:《河南科技大學》2015年碩士論文
【摘要】:銅鋁復合板是一種雙金屬復合材料,不僅具備銅的熱傳導率高,接觸電阻低等優(yōu)點,還兼具鋁的密度小,價格低廉等特點。目前,在軍工、航空航天等高科技領域及散熱基板、電器、建筑等普通民用領域均可見到銅鋁復合板材的身影。本文研究的銅鋁復合板材通過連鑄連軋法制備,利用維氏硬度檢測儀、剝離試驗機、金屬導電率檢測儀、拉伸試驗機等設備對復合板力學性能和導電性能進行了測試,利用SEM、EDS、XRD、TEM等微觀分析儀器研究了結合層的微觀形貌、成分及組織結構,分析了微觀組織與宏觀性能的關聯(lián)性。重點研究了界面層形貌、板材力學性能、板材電導率隨復合板冷軋壓下率變化的規(guī)律以及退火工藝對冷軋?zhí)幚砗髲秃习褰缑鎸咏M織形貌,性能的影響規(guī)律,結果如下:1.采用鑄軋復合法可以制備出結合效果和導電性能良好的銅鋁復合板材,界面層由共晶組織α-Al+Cu Al2以及Cu Al2組成。鑄軋法制備的銅鋁復合板材,其結合強度高于其它復合法制備的復合板,復合板抗拉強度與延伸率均介于同尺寸純銅、純鋁板材之間,趨膚效應的存在使復合板導電溫升曲線和純銅板相近。2.壓下率較高時,冷軋會使鑄軋復合板材界面層發(fā)生斷裂和破碎進而影響復合材料性能;冷軋壓下率從29%逐漸增加到57%時,界面層的破碎程度逐漸加重,剝離強度先迅速減弱后緩慢增強,復合板抗拉強度逐漸增大,延伸率則隨之下降,電導率逐漸降低。3.不同退火工藝處理后的冷軋復合板,其界面層微觀組織,力學性能均產(chǎn)生明顯的變化,退火處理使得破碎的界面層重新變得連續(xù)致密;在300℃-400℃的熱處理條件下,冶金層中存在Cu Al2、Cu9Al4和Cu Al三種銅鋁化合物,隨著溫度升高或退火時間延長,各相的厚度均逐漸增長,板材基體硬度先迅速減小然后保持穩(wěn)定,板材電導率則逐漸回升,剝離強度先逐漸增大,在300℃×3h時達到最大值,繼續(xù)提高退火溫度或者延長退火時間,剝離強度開始逐漸下降。
[Abstract]:Cu-Al composite plate is a kind of bimetallic composite material, which not only has the advantages of high thermal conductivity and low contact resistance of copper, but also has the characteristics of low density and low price of aluminum. At present, in the military industry, aerospace and other high-tech areas and heat dissipation substrate, electrical appliances, buildings and other common civil fields can be seen in copper and aluminum composite sheet figure. The copper-aluminum composite plate studied in this paper was prepared by continuous casting and rolling method. The mechanical and electrical properties of the composite plate were tested by Vickers hardness tester, stripping tester, metal conductivity tester, tensile tester and so on. The microstructure, composition and microstructure of the bonding layer were studied by means of SEM EDS- XRD- TEM, and the relationship between microstructure and macroscopic properties was analyzed. The morphology of interface layer, the mechanical properties of composite plate, the variation of sheet electrical conductivity with cold rolling reduction rate and the influence of annealing process on the microstructure and properties of interfacial layer of composite plate after cold rolling were studied. The results are as follows: 1. Cu-Al composite sheet with good bonding effect and electrical conductivity can be prepared by casting and rolling recombination method. The interface layer is composed of eutectic structure 偽 -Al Cu Al2 and Cu Al2. The bonding strength of Cu-Al composite plate prepared by casting rolling method is higher than that of other composite plates. The tensile strength and elongation of the composite plate are between pure copper and aluminum sheet of the same size. Because of the skin effect, the conductive temperature rise curve of composite plate is close to that of pure copper plate. When the reduction rate is high, the interfacial layer of cast-rolling composite sheet will be broken and broken, and then the properties of composite material will be affected by cold rolling, and when the reduction rate of cold rolling is increased from 29% to 57%, the breaking degree of interface layer will gradually increase. The peeling strength decreased rapidly and then increased slowly, the tensile strength of the composite plate increased gradually, the elongation decreased and the electrical conductivity decreased gradually. The microstructure and mechanical properties of the interfacial layer of the cold-rolled composite plate treated by different annealing processes are obviously changed. Annealing treatment makes the broken interfacial layer become continuous and compact again, and under the heat treatment conditions of 300 鈩,
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