CAJ | 학술논문

采用Gleeble?3500D热模拟试验机在300~550°C，0.001~10 s?1条件下开展了CNTs/Al复合材料热变形行为研究，并基于真应力?应变曲线计算得到了CNTs/Al复合材料在不同应变时的热加工图。利用电子背散射技术分析了变形前后的显微组织。实验结果表明，在设定的温度下，流变应力随着应变速率的增高而增高，而在设定的应变速率下，流变应力随着温度的增高而降低。在高应变速率条件下，可以获得完全再结晶组织。而在低应变速率条件下，只有部分再结晶，主要的软化机制为动态回复。在本研究所采用的实验条件下，CNTs/Al复合材料的热变形最优加工工艺参数为500~550°C，10 s?1。
채용Gleeble?3500D열모의시험궤재300~550°C，0.001~10 s?1조건하개전료CNTs/Al복합재료열변형행위연구，병기우진응력?응변곡선계산득도료CNTs/Al복합재료재불동응변시적열가공도。이용전자배산사기술분석료변형전후적현미조직。실험결과표명，재설정적온도하，류변응력수착응변속솔적증고이증고，이재설정적응변속솔하，류변응력수착온도적증고이강저。재고응변속솔조건하，가이획득완전재결정조직。이재저응변속솔조건하，지유부분재결정，주요적연화궤제위동태회복。재본연구소채용적실험조건하，CNTs/Al복합재료적열변형최우가공공예삼수위500~550°C，10 s?1。
Deformation behaviors of CNTs/Al alloy composite fabricated by the method of flake powder metallurgy were investigated by hot compression tests, which were performed in the temperature range of 300?550 °C and strain rate range of 0.001? 10 s?1 with Gleeble?3500 thermal simulator system. Processing maps of the CNTs/Al alloy at different strains were calculated to study the optimum processing domain. Microstructures before and after hot compressions were characterized by electron backscattered diffraction (EBSD) method. Stress?strain curves indicate that the flow stress increases with the increase of strain rate and the decrease of temperature. The processing maps of the CNTs/Al alloy at different strains show that the optimum processing domain is 500?550 °C, 10 s?1 for hot working. EBSD analysis demonstrates that fully dynamic recrystallization occurs in the optimum processing domain (high strainrate 10 s?1), whereas the main soften mechanism is dynamic recovery at low strain rate (0.001 s?1).