(1. 山東大學(xué) 材料液固結(jié)構(gòu)演變與加工教育部重點(diǎn)實(shí)驗(yàn)室，濟(jì)南 250061；
2. 山東大學(xué) 材料科學(xué)與工程學(xué)院，濟(jì)南 250061)
摘 要: 本文首先制備了含有1.5%(質(zhì)量分?jǐn)?shù))TiC的2024鋁合金粉末，并將其加入AlSi10Mg合金粉末中，形成AlSi10Mg-2024(TiC)混合粉末，然后采用激光選區(qū)熔化工藝對混合粉末成形，并對其沉積態(tài)和T6熱處理態(tài)的顯微組織及力學(xué)性能進(jìn)行了表征。結(jié)果表明：激光選區(qū)熔化過程中2024鋁合金中的TiC顆粒可作為異質(zhì)形核點(diǎn)，促進(jìn)Al形核，進(jìn)而抑制粗大柱狀晶的形成，顯著細(xì)化鋁合金的顯微組織，并弱化了〈100〉//BD(Build direction, 生長方向)絲織構(gòu)的形成。經(jīng)過T6熱處理(520 ℃固溶2 h，190 ℃時(shí)效10 h)后，AlSi10Mg-2024(TiC)合金仍保持較高的力學(xué)性能，抗拉強(qiáng)度達(dá)到400 MPa。而經(jīng)T6熱處理后AlSi10Mg合金的強(qiáng)度僅為260 MPa。這是因?yàn)樘砑?024合金可以引入Cu元素，在時(shí)效過程中析出第二相粒子，強(qiáng)化鋁合金基體。另外，時(shí)效過程中析出的納米Si顆粒也可對T6熱處理后的AlSi10Mg-2024(TiC)合金起到一定強(qiáng)化作用。
關(guān)鍵字: 激光選區(qū)熔化；增材制造；鋁合金；AlSi10Mg；2024鋁合金
（1. Key Laboratory for Liquid-Solid Structural Evolution and Processing of Materials (Ministry of Education), Shandong University, Jinan 250061, China;
2. School of Materials Science and Engineering, Shandong University, Jinan 250061, China）
Abstract:In this work, 2024 alloy powders with 1.5% (mass fraction) TiC nanoparticles were produced first. The special 2024(TiC) alloy powders were added into the widely used AlSi10Mg powders through mechanical mixing. Selective laser melting technique was used to fabricated the samples. The microstructure and mechanical properties of the as-fabricated samples and the samples after T6 heat treatment (solution treated at 520 ℃ for 2 h, aging at 190 ℃ for 10 h) were studied. The results show that the TiC nanoparticles could act as the heterogeneous nucleation site of Al grains, leading to the suppression of coarse columnar grains. As a result, the microstructure could be refined remarkably. Moreover, the strong 〈100〉//BD (Build direction) fiber texture is suppressed largely. After T6 heat treatment, the strength of AlSi10Mg alloy drops to 260 MPa, while the strength of 2024(TiC) modified alloy, i.e. AlSi10Mg-2024(TiC) alloy, maintains at a high level of around 400 MPa. This is because the addition of 2024 alloy will introduce Cu element, which promotes the formation of second-phase particles during subsequent aging treatment, and thus strengthening the aluminum matrix. Moreover, the precipitation of nanoscale Si particles may also help to strengthen the T6-treated AlSi10Mg-2024(TiC) alloy.
Key words: selective laser melting; additive manufacturing; aluminum alloy; AlSi10Mg; 2024 alloy
