(1. 南昌航空大學(xué) 輕合金加工科學(xué)與技術(shù)國(guó)防重點(diǎn)學(xué)科實(shí)驗(yàn)室，南昌 330063；
2. School of Engineering, The Ohio State University, Columbus, OH 43210, USA)
摘 要: 基于KKS相場(chǎng)模型，針對(duì)hcp晶系鎂合金，建立了一個(gè)耦合溶質(zhì)場(chǎng)、流場(chǎng)、取向場(chǎng)和溫度場(chǎng)的多枝晶生長(zhǎng)相場(chǎng)模型。為了描述具有不同晶體學(xué)取向的多枝晶生長(zhǎng)并減少計(jì)算量，該模型采用Kobayashi等提出的通過(guò)擴(kuò)散奇異性來(lái)保持晶粒內(nèi)部取向一致的方法，引入取向場(chǎng)θ來(lái)對(duì)不同晶粒的結(jié)晶取向進(jìn)行描述，實(shí)現(xiàn)了單相場(chǎng)控制不同取向多個(gè)枝晶的生長(zhǎng)。為進(jìn)一步提高計(jì)算效率，在模型求解中使用了二重網(wǎng)格技術(shù)。以AZ91D合金為例，對(duì)純擴(kuò)散下和強(qiáng)迫對(duì)流作用下不同取向多枝晶的生長(zhǎng)行為進(jìn)行了模擬，并與實(shí)驗(yàn)結(jié)果進(jìn)行對(duì)比，模擬結(jié)果與實(shí)驗(yàn)結(jié)果十分吻合。
關(guān)鍵字: 鎂合金；相場(chǎng)法；多枝晶；取向場(chǎng)；計(jì)算機(jī)模擬
（1. National Defence Key Discipline Laboratory of Light Alloy Processing Science and Technology Institute,
Nanchang Hangkong University, Nanchang 330063, China;
2. School of Engineering, The Ohio State University, Columbus, OH 43210, USA）
Abstract:Based on the KKS model which couples concentration field, flow field, orientation field and temperature field, the phase-field model for magnesium alloys with hcp structure was developed. In order to simulate the growth of multiple grains with different preferred growth orientation and reduce calculation amount, a orientation field which keeps the same of orientation in the interior of the grain using the strangeness of diffusion is added to describe the crystallographic orientation, which implements the control of multiple grains with different preferred growth orientation using one phase field controlling equation. The double mesh technique is used to solve the model in order to improve the computing efficiency ulteriorly. Taking AZ91D alloy for example, the dendritic growth of multiple grains with different preferred growth orientation during solidification without and with flow are simulated, the microstructure simulation results are compared with the experimental results, and they are in good agreement in dendritic morphology.
Key words: magnesium alloy; phase-field method; multiple grains; orientation field; computer simulation
