本文關(guān)鍵詞： Cu-0.2Be-XCo合金 熱處理 性能 析出相　出處：《河南科技大學(xué)》2017年碩士論文　論文類型：學(xué)位論文

【摘要】：作為典型的時效強化型銅合金,鈹青銅經(jīng)固溶時效處理后可獲得高的強度/硬度、優(yōu)良的導(dǎo)電/導(dǎo)熱性、較好的耐磨抗蝕性等,廣泛應(yīng)用于航空航天、電子電氣、日用五金等諸多領(lǐng)域。目前,國內(nèi)外大量研究和應(yīng)用的主要是Be含量為1.6%~2.1%的高鈹銅合金,然而由于Be及其化合物毒性較大,且制備加工過程對人體和環(huán)境有害,要求盡量降低合金中Be的含量,但Be含量降低會致使合金力學(xué)性能顯著降低。因此如何通過微合金化手段和熱處理工藝調(diào)控,在最大限度降低Be含量的基礎(chǔ)上,開發(fā)具有優(yōu)良綜合性能的低鈹銅合金具有重要意義。本文在二元低鈹Cu-0.2Be合金的基礎(chǔ)上,通過添加不同含量(0%、0.5%、1.0%)Co元素形成的Cu-0.2Be-XCo合金,研究了Co元素對合金鑄態(tài)、擠壓態(tài)、時效態(tài)組織與性能的影響,并獲得試驗范圍內(nèi)Co元素的較佳添加量為0.5%。以Cu-0.2Be-0.5Co合金為研究對象,考察了時效溫度和時間對合金導(dǎo)電率及顯微硬度的影響,揭示了時效過程中析出相的形貌、尺寸、分布等特征參量的演變規(guī)律,探索了析出相體積分?jǐn)?shù)、導(dǎo)電率及時效時間三者內(nèi)在關(guān)聯(lián)。為進一步提高合金力學(xué)性能,在固溶時效熱處理基礎(chǔ)上,研究了固溶+冷變形+時效對Cu-0.2Be-0.5Co合金性能與組織的影響,確定了較佳的冷變形時效工藝參數(shù)。結(jié)果表明:1.隨著Co元素含量增加,Cu-0.2Be-XCo合金鑄態(tài)、擠壓態(tài)晶粒明顯細(xì)化,顯微硬度提升,導(dǎo)電率下降;經(jīng)460℃時效后不含Co的Cu-0.2Be合金導(dǎo)電率保持在55.9~59.8%IACS,顯微硬度保持在95~100 HV,時效時間在2 h及以上時,Cu-0.2Be-0.5Co合金的綜合性能明顯優(yōu)于Cu-0.2Be-1.0Co合金,在試驗范圍內(nèi)Co元素的較佳添加量為0.5%。2.Cu-0.2Be-0.5Co合金經(jīng)950℃×1 h固溶及440~500℃時效后,導(dǎo)電率和顯微硬度在時效初期急劇升高,時效中期緩慢增加,時效后期趨于穩(wěn)定;在460℃×2 h時效條件下合金析出相為橢球狀Be12Co,并彌散分布于銅基體,導(dǎo)電率及顯微硬度分別為57.1%IACS和243 HV;根據(jù)Cu-0.2Be-0.5Co合金在440~500℃時效過程中導(dǎo)電率隨時效時間的變化趨勢,構(gòu)建了合金的相變動力學(xué)方程和導(dǎo)電率方程。3.Cu-0.2Be-0.5Co合金經(jīng)冷壓縮后導(dǎo)電率隨變形量增加而下降,顯微硬度隨變形量增加而上升;Cu-0.2Be-0.5Co合金較佳冷形變時效工藝為950℃×1 h固溶+50%冷變形+460℃×2 h時效,在此條件下合金導(dǎo)電率和顯微硬度獲得良好匹配,其值分別為58.0%IACS和285 HV。
[Abstract]:As a typical aging strengthened copper alloy, beryllium bronze can obtain high strength / hardness, excellent conductivity / thermal conductivity, good wear resistance and corrosion resistance after solid solution aging treatment. It is widely used in aerospace. At present, a large number of research and application at home and abroad are mainly be content of 1.6% of high beryllium copper alloy, but due to the toxicity of be and its compounds. The preparation process is harmful to human body and environment, so it is necessary to reduce the content of be in alloy as far as possible. However, the mechanical properties of the alloy will be significantly reduced when the content of be is reduced. Therefore, how to minimize the content of be by means of microalloying and heat treatment. It is of great significance to develop low beryllium copper alloy with excellent comprehensive properties. In this paper, on the basis of binary low beryllium Cu-0.2Be alloy, 0.5% different content of beryllium is added. The effect of Co on the microstructure and properties of Cu-0.2Be-XCo alloy formed by Co element was studied. The optimum addition amount of Co in the range of test is 0.5. The Cu-0.2Be-0.5Co alloy is taken as the object of study. The effects of aging temperature and time on the conductivity and microhardness of the alloy were investigated. The evolution rules of the morphology, size and distribution of precipitated phase were revealed, and the volume fraction of precipitated phase was explored. In order to further improve the mechanical properties of the alloy, it is based on the solid solution aging heat treatment. The effect of solution cold deformation aging on the properties and microstructure of Cu-0.2Be-0.5Co alloy was studied. The optimum aging process parameters of cold deformation were determined. The results showed that the grain size of Cu-0.2Be-XCo alloy was finer and the microhardness was increased with the increase of Co content in the as-cast state of Cu-0.2Be-XCo alloy. Conductivity decreased; After aging at 460 鈩，

本文編號：1448409