(1. 華南理工大學(xué) 應(yīng)用化學(xué)系， 廣州 510640;
2. 廣州有色金屬研究院 分析室， 廣州 510651;
3. 中南工業(yè)大學(xué) 粉末冶金研究所， 長(zhǎng)沙 410083)
摘 要: 建立了PIM脫脂過(guò)程中高分子高溫裂解脫除的數(shù)學(xué)模型， 分析了生坯中的應(yīng)力分布， 考察了恒加熱速率、 恒失重速率、 保溫處理工藝等對(duì)生坯應(yīng)力的影響。結(jié)果顯示， 生坯內(nèi)氣體壓力、 徑向應(yīng)力、 切向應(yīng)力分布呈現(xiàn)中高外低分布， 徑向應(yīng)力在生坯表面為零， 而切向應(yīng)力在表面不為零。 與恒加熱速率比較， 恒失重速率和保溫處理工藝可以有效降低生坯應(yīng)力，但熱脫脂工藝時(shí)間仍較長(zhǎng)。 采用恒應(yīng)力方法對(duì)工藝進(jìn)行優(yōu)化設(shè)計(jì)， 既可以有效降低生坯內(nèi)應(yīng)力， 又可以大幅度縮短脫脂工藝時(shí)間。
關(guān)鍵字: PIM； 脫脂； 數(shù)學(xué)模型； 工藝優(yōu)化
（1. Department of Applied Chemistry, South China University of Technology, Guangzhou 510640, P.R.China;
2. Guangzhou Nonferrous Metal Research Institute, Guangzhou 510651, P.R.China;
3. State Key Lab for Powder Metallurgy, Central South University of Technology, Changsha 410083, P.R.China）
Abstract:A numerical model of polymer debinding in PIM was proposed. The stress distribution in greenware was analyzed and the effects such as linear heating rate, holdingtime heating, mass loss ratecontrolled program on the stress was investigated. The results show that the distribution of inner gas pressure， radial and tangential stresses exhibit their maximum values at center and decrease as the position shifts away from the center to the surface. At the surface,the radial stress drops to zero, but the tangential stress does not. By comparison of holdingtime heating and mass loss ratecontrolled programs with linear heatingrate program, the maximum stresses at the center decrease much, but the process time shortens a little. The optimized parameters can be drawn by the isostress method to minimize the stresses and process time.
Key words: PIM； debinding； numerical model； optimized parameters
