中文摘要：

采用Gleeble3800热模拟试验机,对NLC法制备的三种铝合金进行触变压缩变形行为研究,考虑热膨胀因素对流动应力的影响,对真应力-应变曲线数据进行修正.结果表明：其真应力-应变曲线均为动态再结晶型,随着变形量的增加,流动应力出现急剧下降,主要是由于外力作用下固体骨架迅速坍塌以及液相被挤出到试样表面.触变强度受变形温度、应变速率、变形量和材料初始强度的影响较大,而稳态应力仅受材料初始强度的影响较大.峰值应变值在0.06左右,稳态应变值在0.2～0.3之间.在实验设备设计与控制上保障了数据的可靠性,为建立半固态合金的本构关系奠定了基础.

英文摘要：

The thixo-compression deformation behavior of three aluminum alloys prepared by near-liquidus-casting were investigated on the Gleeble 3800 thermo-mechanical simulator.The true stress-strain curves were modified considering the influence of thermal expansion on flowing stress.The results showed that the true stress-strain curves are all of the type of dynamic recrystallization,and that the flowing stress decreases sharply with increasing strain mainly because of the rapid collapse of solid skeleton under the action of external force with the liquid squeezed out to the sample surface.The peak stress is affected obviously by deformation temperature,strain rate,strain and initial strength of materials,while the steady stress is just affected obviously by the initial strength of materials.The peak strain value is around 0.06,and the steady strain value is between 0.2 and 0.3.The reliable data resulting from the proper design and control of experimental setup lays a foundation on which the semi-solid constitutive relationship is available to establish.