(西安理工大學(xué) 材料科學(xué)與工程學(xué)院，西安 710048)
摘 要: 在MATLAB模擬平臺(tái)上基于CA-FE法(元胞自動(dòng)機(jī)-有限元)結(jié)合晶粒的形核與生長(zhǎng)理論，建立了TC4鈦合金瞬態(tài)焊接溫度場(chǎng)下熔池內(nèi)微觀組織演變的數(shù)值計(jì)算模型，基于該模型對(duì)焊接瞬態(tài)溫度場(chǎng)及其作用下的微觀組織演變進(jìn)行了模擬。結(jié)果表明：溫度場(chǎng)的計(jì)算結(jié)果符合焊接熱過(guò)程局部熱量集中且高度動(dòng)態(tài)變化的特點(diǎn)，熔池邊緣先形核，在溫度梯度作用下晶粒以柱狀晶的形式向熔池中心生長(zhǎng)，最后形成粗大的柱狀晶組織，固態(tài)相變階段，熔池內(nèi)組織迅速轉(zhuǎn)變?yōu)棣?'''馬氏體。對(duì)模擬結(jié)果進(jìn)行驗(yàn)證性實(shí)驗(yàn)，模擬結(jié)果與實(shí)驗(yàn)結(jié)果吻合性良好，顯示所建數(shù)值計(jì)算模型可靠性較高。
關(guān)鍵字: TC4合金；熔池；微觀組織；數(shù)值模擬；CA-FE法
（School of Material Science and Engineering, Xi’an University of Technology, Xi’an 710048, China）
Abstract:Based on the CA-FE method (cell automaton-finite element) combined with grain nucleation and growth theory, a numerical calculation model for microstructure evolution in TC4 titanium alloy molten pool under transient welding temperature field was established on MATLAB simulation platform. Based on the model, the welding transient temperature field and the microstructure evolution under its influence were simulated. The results show that, the calculation results of the temperature field are consistent with the characteristics of local heat concentration and high dynamic changes in the welding heat process. The edge of the molten pool is first nucleated, and under the action of the temperature gradient, the crystal grains grow in the form of columnar crystals to the center of the molten pool and finally form a coarse columnar crystal structure. The microstructure in the molten pool rapidly transforms into α'''' martensite in the solid phase transformation stage. The verification experiment was carried out on the simulation results, and the simulation results are in good agreement with the experimental results, indicating that the model is highly reliable.
Key words: TC4 alloy; molten pool; microstructure; numerical simulation; CA-FE method
