PMMA高弹态热压变形行为

Deformation behavior of high elastic state PMMA under hot compression

从技术上分析PMMA在Tg^Tf高弹态温度区间变形的相-态意义,使用黄金分割法在Tg^Tf温度区间划分低温高弹变形和高温高弹变形温度区域,同时设计高弹态热压实验温度,沿用冷压变形研究的镦粗变形模式和试样进行4种变形速度和3种变形程度的高弹态热压变形实验。实验结果表明,PMMA在低温高弹变形温度下呈"软而韧"性质,在高温高弹态变形温度下趋于粘流变形,极限变形程度较冷压变形提高,卸载后的最大回弹率5.9%,平均回弹率2.3%,由此认为,PMMA高弹态热锻技术具有可控的定形性并具有生产应用价值。

Based on traditional manufacturing concept,the significance of phase structure-condensed state about PMMA deforming in Tg～Tf temperature range are discussed.To this polymer,low and high temperature zones for high-elastic（rubber-like） deforming were plot out between Tg and Tf using golden section,and meantime their experimental temperatures under high-elastic（rubber-like） state were designed for hot compression.As upsetting deformation and specimen in cold compression study recently published,hot compression experiments for high-elastic state PMMA are done by using four kinds of deformation rate and three kinds of deformation degree.In the experiments,PMMA would be behaved with soft and tough property during low temperature deforming under its high elastic state,and would have tendency of viscous flow deforming during high temperature deforming under its high elastic state.The limit deformation degree would be increased;the maximum and average ratios of strain recovery were respectively 5.9% and 2.3% after load removal.Therefore,the shape fixbility can be controlled during hot forged PMMA under high-elastic state and this technique will be usable in manufacturing.