α(Al)晶粒形核的影響
(1. 蘭州理工大學(xué) 甘肅省有色金屬新材料省部共建國(guó)家重點(diǎn)實(shí)驗(yàn)室，蘭州 730050；
2. 蘭州理工大學(xué) 有色金屬合金及加工教育部重點(diǎn)實(shí)驗(yàn)室，蘭州 730050)
摘 要: 研究TiC和TiAl3細(xì)化工業(yè)純鋁時(shí)TiAl3的存在對(duì)TiC在鋁基體中分布及α(Al)晶粒形核的影響，分析Al-Ti-C晶粒細(xì)化機(jī)制。結(jié)果表明：TiC單獨(dú)作為工業(yè)純鋁的晶粒細(xì)化劑時(shí)，大量TiC被α(Al)晶粒推向樹(shù)枝晶的晶界處，從而限制了TiC的異質(zhì)形核作用；當(dāng)TiC和TiAl3共同作為晶粒細(xì)化劑時(shí)，在α(Al)晶粒內(nèi)部出現(xiàn)了大量TiC粒子，大量的TiC粒子成為了α(Al)的結(jié)晶核心，并且在TiC顆粒和鋁基體的界面處存在“富Ti過(guò)渡區(qū)”；TiAl3在鋁熔體中分解釋放出Ti原子并向TiC粒子周圍偏聚，形成的“TiC/鋁熔體界面富Ti過(guò)渡區(qū)” 改善了TiC與α(Al)的結(jié)構(gòu)適應(yīng)性，降低了TiC粒子的表面張力，促進(jìn)了TiC粒子在鋁熔體中的均勻分布，提高了其形核能力。
關(guān)鍵字: Al-TiC中間合金；Al-TiAl3中間合金；富Ti過(guò)渡區(qū)；α(Al)；形核機(jī)理
aluminum matrix and nucleation of α(Al) grain
（1. State Key Laboratory of Gansu Advanced Non-ferrous Metal Materials, Lanzhou University of Technology,
Lanzhou 730050, China;
2. Key Laboratory of Non-ferrous Metal Alloys, Ministry of Education, Lanzhou University of Technology,
Lanzhou 730050, China）
Abstract:The effect of TiAl3 on the distribution of TiC particles in aluminum matrix and nucleation of α(Al) grain was studied when the TiC and TiAl3 refining industry aluminum, and the nucleation mechanism of Al-Ti-C grain refiner were discussed. The results show that when TiC alone is used as the nucleation phase, most of the TiC is pushed into the grain boundaries by the α(Al) dendrites and the nucleation of TiC is restricted. On the other hand, when TiC and TiAl3 refine the industry aluminum together, most of the TiC particles are found within the α(Al) grains and nucleation occurs on TiC particles, and there is a Ti transition zone between TiC and aluminum interface. TiAl3 releases Ti atoms in aluminum melt, Ti atoms congregate to the TiC surface, and ultimately forming TiC/aluminum interface Ti transition zone, which not only improves the structure of adaptability and wettability between TiC and Al , but also reduces the surface tension of TiC particles, which making a lot of TiC particles can be uniformly distributed in the aluminum melt, which advance α(Al) core and heterogeneous nucleation in the aluminum melt solidification.
Key words: Al-TiC mast alloy; Al-TiAl3 mast alloy; Ti transition zone; α(Al); nucleation mechanism
