摘要
消失模铸造过程中,泡沫的动态热解过程对金属液充型影响显著,掌握泡沫热解行为对消失模铸造工艺设计与优化有重要作用。在纯空气气氛下,利用热重分析仪对不同升温速率的EPS和St-MMA共聚料的热氧化分解过程进行了研究。发现热氧化分解过程中,EPS分解温度较St-MMA略高,利用等转化率法计算得到EPS和St-MMA共聚料的平均表观活化能分别为86.8和82.5kJ·mol^(-1)。利用z(α)模板曲线确定EPS泡沫热氧化分解过程属于相界面控制反应机理R3,反应受界面反应速率控制,由表面至中心发生反应。利用模型拟合方法得到St-MMA泡沫的分解过程较为复杂,受多种反应机制控制。
In lost foam casting,the dynamic thermal degradation process of lost foam patterns under high temperature has a significant effect on molten metal filling appearance.The thermo-oxidative behaviors of EPS and St-MMA were investigated using Thermogravimetric analysis（TGA）in pure air atmosphere at multiple linear heating rates.The apparent activation energy of EPS and St-MMA was determined by the iso-conversional methods.The average apparent activation energy of EPS and St-MMA reaches 86.8 kJ·mol-1 and 82.5 kJ·mol-1,respectively.Furthermore,the master plot z（α）was adopted to compare experimental results and general reaction mechanism functions,and the reaction mechanism of EPS is determined by phase boundary controlled reaction model R3.While the St-MMA reaction mechanism function was acquired by the model fitting method using nonlinear least square method,reflecting its complicated degradation mechanism.The simulated kinetic reaction rate model of EPS and St-MMA can supply accurate theoretical dataset for modeling the dynamic thermal degradation process in lost foam casting.
作者
李曦
沈旭
殷亚军
周建新
解明国
刘伟
Li Xi1 , Shen Xu1, Yin Yajun1 , Zhou Jianxin1 Xie Mingguo2, Liu Wei2(1. State Key Laboratory of Materials Processing and Die ＆Mould Technology, Huazhong University of Science and Technology; 2. Anhui Heli Co., Ltd)
出处
《特种铸造及有色合金》
CAS
CSCD
北大核心
2018年第10期1088-1092,共5页
Special Casting & Nonferrous Alloys
基金
国家自然科学基金资助项目(51775205
51605174)
