(1. 中南大學(xué) 粉末冶金國家重點(diǎn)實(shí)驗(yàn)室，長沙 410083；2. 株洲中航動(dòng)力精密鑄造有限公司，株洲 412000)
摘 要: 針對(duì)當(dāng)前雀斑判據(jù)在合金成分上存在的不足，構(gòu)建一個(gè)基于高溫合金成分的雀斑預(yù)測模型并對(duì)其進(jìn)行了驗(yàn)證。通過對(duì)合金各元素的密度溶質(zhì)膨脹系數(shù)β和密度溫度膨脹系數(shù)βT的計(jì)算，定量分析其在凝固過程中對(duì)糊狀區(qū)液相密度的影響。通過定義一個(gè)雀斑形成傾向因子P，量化各個(gè)元素對(duì)雀斑形成的影響大小。并在此基礎(chǔ)上，構(gòu)建一個(gè)慮及合金成分的雀斑預(yù)測模型，該模型可以預(yù)測不同組分的合金和雀斑形成之間影響規(guī)律。3種不同來源的k值(如實(shí)驗(yàn)值、二元合金相圖和Thermo-Calc計(jì)算的平衡分配系數(shù))被代入該模型計(jì)算，驗(yàn)證哪種k值能更好地預(yù)測雀斑形成。結(jié)果表明：基于二元合金相圖的k值，預(yù)測結(jié)果與實(shí)驗(yàn)結(jié)果擬合較差，其線性擬合優(yōu)度R2最大時(shí)僅為0.4；而采用實(shí)驗(yàn)和Thermo-Calc的k值，擬合較好，v2最大值分別達(dá)到0.87和0.95。最后，計(jì)算SX系列合金的P值，結(jié)果顯示：單位含量的Hf元素對(duì)雀斑有最強(qiáng)的抑制作用，Ta元素的抑制作用次之；Al、Re元素對(duì)雀斑有較強(qiáng)的促進(jìn)作用，W元素的促進(jìn)作用次之。
關(guān)鍵字: 雀斑；高溫合金；成分；雀斑形成傾向因子；平衡分配系數(shù)；預(yù)測模型
（1. State Key Laboratory of Powder Metallurgy, Central South University, Changsha 410083, China;
2. Zhuzhou AVIC Power Investment Casting Co., Ltd., Zhuzhou 412000, China）
Abstract:Aiming at the currently shortage of the freckle criterion in the alloy constituents, a constituent-based freckle predictor for nickel-base suppalloy was modeled and verified by the experiment data. The effect of each element on the liquid density was quantitatively analyzed by calculating the solutal expansion coefficient β and the thermal expansion coefficient βT of each element. The impact of each element was quantified by defining a freckle formation tendency factor. Based on calculations of these variables, a constituent-based freckle predictor was modeled, which can predict the influence between different alloy constituents and freckle formation. Three different equilibrium distribution coefficients k were taken into this model and verified which was the best k value to predict freckle. The results show that the fitting of the number of freckles using the k value based on binary phase diagram is poor, and the linear goodness-of-fit (R2) maximum is only 0.4; while using the k values of experiment and Thermo-Calc the fitting is good, and the maximum R2 reach 0.87 and 0.95, respectively. Finally, the P values were calculated for the SX alloys, and the results show that the hafnium has the strongest influence on freckle prevention, tantalum also has beneficial effects though not as pronounced as hafnium; aluminum and rhenium have the stronger promoting effect on freckles, and tungsten is the second.
Key words: freckle; superalloy; constituent; freckle formation tendency factor; equilibrium distribution coefficient; prediction model
