(1. 武漢大學(xué) 物理科學(xué)與技術(shù)學(xué)院，武漢 430072；
2. 湖南金聯(lián)星特種材料股份有限公司，岳陽(yáng) 414005)
摘 要: 以Al、K2TiF6、KBF4和Al-20Sr(質(zhì)量分?jǐn)?shù)，%)中間合金為原料，利用三步加料法和熱擠壓工藝制備Al-5Ti-1B-10Sr復(fù)合中間合金線材(d 9.5 mm)。該線材表面光滑，無(wú)氣泡、起皮、裂紋等缺陷。組織結(jié)構(gòu)分析表明：金屬間化合物Al4Sr相為塊狀，平均長(zhǎng)度為43.2 μm，寬度為26.8 μm，其內(nèi)部或邊緣存在許多孔洞和細(xì)縫； Al3Ti相呈顆粒狀，平均直徑為14.4 μm；TiB2顆粒非常細(xì)小，平均尺寸為1.42 μm，其中95.77%為尺寸≤1.97 μm以下的顆粒。將該復(fù)合中間合金應(yīng)用于Al-13Si合金的細(xì)化與變質(zhì)處理后，合金基體的α(Al)晶粒得到明顯細(xì)化，共晶Si相也由粗大的針狀組織轉(zhuǎn)變成細(xì)小的纖維狀或顆粒狀結(jié)構(gòu)；同時(shí)，Al-13Si合金的硬度提高43.2%，達(dá)到96.5HB，細(xì)化和變質(zhì)效果明顯。
關(guān)鍵字: Al-5Ti-1B-10Sr中間合金線材；細(xì)化；變質(zhì)；微結(jié)構(gòu)；硬度
（1. School of Physics and Technology, Wuhan University, Wuhan 430072, China;
2. Hunan Jinlianxing Special Materials Technology Co., Ltd., Yueyang 414005, China）
Abstract:The Al-5Ti-1B-10Sr master alloy wire (d 9.5 mm) was prepared by three-stage-feedstock method and hot extrusion process, with pure Al, K2TiF6, KBF4 and Al-20Sr master alloy (mass fraction, %) as raw materials. The wire surface is smooth, and without bubbles, peeling and cracks. The results show that, the Al4Sr phase is in the shape of block with many pores and cracks, and with an average size of 43.2 μm in length and 26.8 μm in width; the Al3Ti phase exhibits granular shapes with an average diameter of 14.4 μm; the TiB2 phase is very fine with an average size of 1.42 μm, and the percent of TiB2 particles with size no larger than 1.97 μm reaches 95.77%. When Al-5Ti-1B-10Sr is added into the Al-13Si alloy, not only the grain size of α(Al) is significantly refined, but also the eutectic Si phase changes from the coarse acicular into fine fibrous or granular. Compared with the untreated Al-13Si alloy, the hardness increases by 43.2% after adding Al-5Ti-1B-10Sr, up to 96.5HB, showing a good performance of both refinement and modification.
Key words: Al-5Ti-1B-10Sr master alloy wire; refinement; modification; microstructure; hardness
