【摘要】：銅合金是應(yīng)用最為廣泛的金屬材料之一,其最主要的應(yīng)用領(lǐng)域?yàn)殡姎夂碗娮庸I(yè),占銅總消耗量50%以上。作為原材料用于生產(chǎn)和制造電纜、開關(guān)、線路板以及電機(jī)等產(chǎn)品；在機(jī)械、車輛的生產(chǎn)中,主要用于生產(chǎn)工業(yè)用閥門和配件、儀表、軸承、耐高溫模具、熱交換器等。使用傳統(tǒng)方法澆鑄的銅合金容易產(chǎn)生氣孔、縮松、裂紋以及偏析等常見的鑄造缺陷,組織均勻性較差,嚴(yán)重影響了銅合金的使用性能和使用壽命。同時,由于銅合金的熔點(diǎn)高,在擠壓鑄造的過程中存在模具使用壽命短的致命問題。半固態(tài)加工技術(shù)以其工藝流程較短、充型過程平穩(wěn)、能耗低、模具使用壽命長等優(yōu)點(diǎn)被認(rèn)為是21世紀(jì)最有前途的材料加工成形方法,半固態(tài)加工制備的零件組織致密,力學(xué)性能好而便于機(jī)械加工,近終成形使得機(jī)械加工時加工量減少,而半固態(tài)漿料的制備是該技術(shù)的關(guān)鍵所在。采用半固態(tài)成形技術(shù)加工銅合金,有利于降低澆注時模具的溫度從而大幅提高模具的使用壽命,改善銅合金組織的均勻性從而提高其使用壽命、擴(kuò)大其應(yīng)用范圍。本文采用轉(zhuǎn)棒誘導(dǎo)形核法制備CuSn10合金半固態(tài)漿料,并對半固態(tài)漿料進(jìn)行擠壓鑄造成形獲得零件,主要研究內(nèi)容如下：采用轉(zhuǎn)棒誘導(dǎo)形核法制備CuSn10合金半固態(tài)漿料,分析轉(zhuǎn)棒直徑、轉(zhuǎn)棒轉(zhuǎn)速對半固態(tài)漿料顯微組織的影響。實(shí)驗(yàn)結(jié)果表明,轉(zhuǎn)棒誘導(dǎo)形核法對CuSn10合金熔體的凝固有明顯的促進(jìn)形核作用,α-Cu相得到細(xì)化,枝晶狀組織被消除,明顯改善了組織不均勻的問題。但是在不同實(shí)驗(yàn)參數(shù)下獲得的半固態(tài)坯料組織有所不同：外徑為e45mm和(?)75mm的不銹鋼轉(zhuǎn)棒在相同轉(zhuǎn)速下制備的漿料相比,(?)75mm獲得的坯料微觀組織中晶粒細(xì)化和球化效果更好,組織分布更加均勻；通過對(?)75mm的不銹鋼轉(zhuǎn)棒在不同轉(zhuǎn)速條件下制備的漿料比較發(fā)現(xiàn),隨著轉(zhuǎn)棒轉(zhuǎn)速的提高,轉(zhuǎn)棒的誘導(dǎo)促進(jìn)形核作用呈現(xiàn)出先增強(qiáng)后減弱的趨勢,而并非簡單的逐步增強(qiáng)的趨勢。當(dāng)澆注溫度為1080℃(低過熱度狀態(tài)),轉(zhuǎn)棒轉(zhuǎn)速為500r/min時,獲得的漿料組織中晶粒細(xì)化效果最好,晶粒平均直徑達(dá)到42.3 gm,形狀因子為1.58,同時組織中液相率最高為23.2%。針對所制備的合金半固態(tài)漿料進(jìn)行擠壓鑄造成形,分析壓力、壓頭壓速對零件顯微組織和抗拉強(qiáng)度的影響。實(shí)驗(yàn)結(jié)果表明：壓頭壓速一定時,隨著壓力的增加,零件的抗拉強(qiáng)度隨之提高,從95.3MPa提高到232.4MPa；壓力一定時,隨著壓頭壓速的提高,零件的抗拉強(qiáng)度也隨之提高,從199.2MPa提高到232.4MPa1。與液態(tài)擠壓鑄造成形相比,半固態(tài)擠壓鑄造制備的零件抗拉強(qiáng)度從183.1MPa提高到232.4MPa,提高了26%；延伸率從原來的2.97%提高到12.1%,提高了4.1倍。通過對拉伸試樣斷口進(jìn)行掃描分析發(fā)現(xiàn),隨著壓力和壓頭壓速的提高,獲得的零件組織更加致密,零件的的拉伸斷裂方式為準(zhǔn)解離斷裂。
[Abstract]:Copper alloy is one of the most widely used metal materials. Its main application fields are electrical and electronic industries, accounting for more than 50% of the total copper consumption. Used as raw materials for producing and manufacturing cables, switches, circuit boards and motors, etc. In the production of machinery and vehicles, it is mainly used in the production of industrial valves and accessories, instruments, bearings, high temperature resistant dies, heat exchangers, etc. The common casting defects, such as porosity, shrinkage, crack and segregation, are easily produced in the copper alloy cast by the traditional method, and the structure uniformity is poor, which seriously affects the service performance and service life of the copper alloy. At the same time, due to the high melting point of copper alloy, die life is short in squeeze casting. Semi-solid processing technology is considered to be the most promising material forming method in the 21st century because of its advantages such as short technological process, stable filling process, low energy consumption and long service life of die. The mechanical properties are good and easy to be machined. Near-end forming reduces the machining quantity, and the preparation of semi-solid slurry is the key of this technology. Using semi-solid forming technology to process copper alloy is beneficial to reduce the mold temperature and increase the service life of die, improve the structure uniformity of copper alloy and extend its application range. In this paper, CuSn10 alloy semi-solid slurry was prepared by rod-induced nucleation method, and the semi-solid slurry was formed by squeeze casting. The main research contents are as follows: the semi-solid slurry of CuSn10 alloy was prepared by rotor-induced nucleation method. The effect of rotating rod diameter and rotating speed on microstructure of semi-solid slurry was analyzed. The experimental results show that the rod-induced nucleation method can obviously promote the nucleation of CuSn10 alloy melt, the 偽 -Cu phase is refined, the dendritic structure is eliminated, and the problem of microstructure inhomogeneity is obviously improved. However, the microstructure of semisolid billets obtained under different experimental parameters is different. Compared with the slurry prepared with stainless steel rotating rods with outer diameter of e45mm and (?) 75mm at the same speed, the microstructure of the billets obtained by (?) 75mm is better in grain refinement and spheroidization. The results showed that with the increase of rotating speed, the nucleation of stainless steel rotating rod of 75mm increased first and then weakened, the microstructure distribution was more uniform, and the results showed that with the increase of rotating speed, the nucleation effect of stainless steel rotor rod increased first and then weakened, and the results showed that with the increase of rotating speed, the nucleation of stainless steel rotor rod increased firstly and then weakened. Rather than a simple incremental trend. When the pouring temperature is 1080 鈩，

本文編號：2149697