【摘要】：由于具有高強(qiáng)度、高導(dǎo)電性和無磁致熱效應(yīng)等優(yōu)點(diǎn),Cu-Ni-Si合金被認(rèn)為是最有希望取代Cu-Be合金、成為新型引線框架的主要候選材料。然而,傳統(tǒng)熔鑄法制備Cu-Ni-Si合金時(shí)極易在銅晶界上形成網(wǎng)狀不導(dǎo)電金屬間化合物相,從而影響合金的強(qiáng)度和導(dǎo)電性,且從鑄錠到薄板的加工工藝繁瑣,生產(chǎn)成本高、效率低。本文以Cu、Ni和Si單質(zhì)粉末為原料,結(jié)合熱壓燒結(jié)制備Cu-Ni-Si合金塊體,通過對(duì)燒結(jié)體的密度、硬度、導(dǎo)電率和晶粒尺度等進(jìn)行測(cè)量,探索了燒結(jié)溫度和燒結(jié)時(shí)間對(duì)混合粉末壓坯致密化行為的影響,確定了最佳的燒結(jié)工藝并對(duì)燒結(jié)體的顯微結(jié)構(gòu)進(jìn)行了表征。隨后,通過實(shí)驗(yàn)研究確定了 Ni/Si質(zhì)量比對(duì)Cu-Ni-Si合金強(qiáng)度和導(dǎo)電率的影響規(guī)律,考察了固溶和時(shí)效處理對(duì)燒結(jié)態(tài)Cu-Ni-Si合金的強(qiáng)度和導(dǎo)電率的影響。最后,積極探索了一種Cu-Ni-Si合金薄板的快速成形工藝,即利用直接粉末軋制技術(shù)通過對(duì)Cu、Ni和Si單質(zhì)混合粉末體系進(jìn)行軋制成形和氣氛燒結(jié),制備出了厚度在0.3mm左右的Cu-Ni-Si合金薄板,并對(duì)其強(qiáng)度和導(dǎo)電性進(jìn)行了測(cè)試分析。本文得到主要結(jié)論如下:1.燒結(jié)態(tài)Cu-Ni-Si合金組織主要為:基體相α-Cu(Ni, Si)、晶界相Ni31Si12及晶內(nèi)相δ-Ni2Si組成,其中Ni31Si12相為直徑3-5μm的顆粒,主要分布于Cu基體粉末的邊界處,δ-Ni2Si相的直徑小于1μm,彌散分布于銅基體晶粒內(nèi)部。與普通熔鑄態(tài)Cu-Ni-Si合金相比發(fā)現(xiàn),粉末燒結(jié)法制備確能抑制晶界上網(wǎng)狀Ni31 Si12結(jié)構(gòu)的出現(xiàn)。2.隨著燒結(jié)溫度的升高或燒結(jié)時(shí)間的延長(zhǎng),燒結(jié)體的密度從8.13g/cm~3上升到8.71g/cm~3,燒結(jié)體的硬度從99.1HV增大到134.7HV,燒結(jié)體的導(dǎo)電率從23.67%IACS提高到28.78%IACS;銅粉末基體的晶粒尺寸逐漸變大,進(jìn)而致使合金導(dǎo)電率略微下降。因此,確定了最佳的Cu-Ni-Si合金塊體的燒結(jié)工藝參數(shù)為:燒結(jié)溫度為900℃、燒結(jié)時(shí)間1h;當(dāng)Cu含量為90wt.%、Ni、Si質(zhì)量比為5.4:1時(shí),燒結(jié)態(tài)Cu-Ni-Si合金的導(dǎo)電率和硬度均達(dá)到較高的數(shù)值,即29.8%IACS和134HV。3.經(jīng)固溶和時(shí)效處理后,Ni、Si固溶原子從Cu基體中析出形成彌散分布的δ-Ni2Si析出相,由于δ-Ni2Si相對(duì)合金導(dǎo)電率影響較小,而且對(duì)Cu-Ni-Si合金還存在時(shí)效強(qiáng)化的作用,其導(dǎo)電率和硬度較燒結(jié)態(tài)分別提高了 18.72%和73.13%。4.相比氣霧化Cu單質(zhì)粉末,電解Cu單質(zhì)粉末更易于軋制成形。一道次軋制后Cu-Ni-Si生坯板材韌性好且不易斷裂,其長(zhǎng)度可達(dá)到170mm; Cu-Ni-Si生坯板材經(jīng)二道次軋制后其致密度和厚度分別可達(dá)到81%和0.38mm;而經(jīng)三道次軋制后, Cu-Ni-Si生坯板材邊緣出現(xiàn)卷曲和開裂現(xiàn)象,且表面發(fā)黑,嚴(yán)重影響到Cu-Ni-Si合金薄板的抗拉強(qiáng)度和美觀程度。5.初次燒結(jié)(燒結(jié)溫度900℃、燒結(jié)時(shí)間1h)后Cu-Ni-Si合金板材的致密度從73%逐漸增大至92%,但Cu基體表面存在較多空洞或缺陷,合金板材并未實(shí)現(xiàn)完全燒結(jié),因此對(duì)Cu-Ni-Si板材進(jìn)行二次燒結(jié)(燒結(jié)溫度950℃、燒結(jié)時(shí)間1h),獲得的板材組織中顆粒間結(jié)合緊密,同時(shí)Cu-Ni-Si合金板材的導(dǎo)電率、致密度、抗拉強(qiáng)度和延伸率分別為31%IACS、93%、609.74MPa 和 6.04%。
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圖片說明：粉末軋機(jī)及純Cu粉末軋制示意圖
[Abstract]:The Cu-Ni-Si alloy is considered to be the most promising candidate for the lead frame due to the advantages of high strength, high electrical conductivity and no magneto-caloric effect. However, when a Cu-Ni-Si alloy is prepared by a conventional fusion casting method, a mesh-like non-conductive intermetallic compound phase is easily formed on the copper grain boundary, so that the strength and the conductivity of the alloy are influenced, and the processing technique from the ingot to the thin plate is complex, the production cost is high, and the efficiency is low. In this paper, Cu, Ni and Si elementary powder are used as raw materials, and the Cu-Ni-Si alloy block is prepared by hot-pressing and sintering, and the influence of the sintering temperature and the sintering time on the densification behavior of the mixed powder compact is investigated by measuring the density, the hardness, the conductivity and the grain size of the sintered body. The optimum sintering process was determined and the microstructure of the sintered body was characterized. The influence of the Ni/ Si mass ratio on the strength and the conductivity of the Cu-Ni-Si alloy was determined by the experimental study, and the effect of the solution and aging treatment on the strength and the conductivity of the sintered Cu-Ni-Si alloy was investigated. In the end, a rapid prototyping process of a Cu-Ni-Si alloy sheet is actively explored, that is, a Cu-Ni-Si alloy sheet having a thickness of about 0.3 mm is prepared by rolling and forming a mixed powder system of Cu, Ni and Si by direct powder rolling technology. And the strength and the electrical conductivity are tested and analyzed. The main conclusions are as follows:1. The sintered Cu-Ni-Si alloy is mainly composed of a matrix phase Ni-Cu (Ni, Si), a grain boundary phase Ni31Si12 and a crystal inner phase Ni-Ni2Si, wherein the Ni31Si12 phase is a particle with a diameter of 3-5 & mu; m, and is mainly distributed at the boundary of the Cu matrix powder; and the diameter of the Ni-Ni2Si phase is less than 1. m And the dispersion is distributed inside the crystal grains of the copper matrix. Compared with the common cast-in-state Cu-Ni-Si alloy, it is found that the preparation of the powder sintering method can restrain the appearance of the net-like Ni31 Si12 structure on the grain boundary. As the sintering temperature is raised or the sintering time is prolonged, the density of the sintered body is increased from 8.13 g/ cm to 3, the hardness of the sintered body is increased from 99.1 HV to 134.7 HV, and the conductive rate of the sintered body is increased from 23.67% IACS to 28.78% IACS, and the grain size of the copper powder matrix is gradually increased, which in turn causes a slight decrease in the conductivity of the alloy. Therefore, the optimum sintering process parameters of the Cu-Ni-Si alloy block are determined as follows: the sintering temperature is 900 DEG C, the sintering time is 1 h, and when the Cu content is 90 wt. When the mass ratio of Ni and Si was 5.4:1, the conductivity and hardness of the sintered Cu-Ni-Si alloy reached a higher value, that is, 29.8% IACS and 134HV.3. After the solid solution and the aging treatment, the solution atoms of Ni and Si are separated out from the Cu matrix to form a dispersion-distributed Ni-Ni2Si precipitation phase, and the effect of aging strengthening is also existed for the Cu-Ni-Si alloy due to the small influence on the conductivity of the Ni-Ni2Si relative to the alloy, Its conductivity and hardness were increased by 18.72% and 73.13%, respectively. Compared with the gas-atomized Cu elementary powder, the elemental powder of the electrolytic Cu is easier to roll and form. the toughness of the Cu-Ni-Si green plate after a secondary rolling is good, the toughness is not easy to break, the length of the Cu-Ni-Si green sheet material can reach 170 mm, and the density and the thickness of the Cu-Ni-Si green sheet material can reach 81 percent and 0.38 mm respectively after the two pass rolling, and after three times of rolling, the edge of the Cu-Ni-Si green sheet material is curled and cracked, and the surface is blackened, The tensile strength and the aesthetic degree of the Cu-Ni-Si alloy sheet are seriously affected. The density of Cu-Ni-Si alloy sheet was gradually increased from 73% to 92% after primary sintering (sintering temperature 900 鈩，

本文編號(hào)：2512458