A2017合金半固态压缩的变形机制和成形性能

利用Gleeble-1500热学-力学模拟机,对A2017半固态合金进行半固态压缩变形实验,分析了应力-应变曲线和组织变化,研究了压缩变形机制及成形性能结果表明,用单辊搅拌冷却(SCR)技术制备的A2017半固态合金的组织为细小均匀的非枝晶等轴晶,二次加热后可转化为均匀的球形晶和共晶液相组成的半固态组织;A2017合金半固态压缩变形的塑性好、变形抗力低;随着变形温度的升高或者变形速率的降低,变形的抗力降低.在稳定的流动变形阶段,A2017合金的半固态变形机制主要由液相流动和固相颗粒的转动与滑动组成,触变性能稳定,最大半固态加工变形范围为60%左右.

Deformation mechanism and forming property of A2017 alloys during compression in semi--solid state

Semi-solid A2017 alloys were compressed in semi-solid state by means of Gleeble-1500 thermal-mechanical simulator. The microstructures and relationship between the true stress and the true strain were analyzed. The deformation mechanism and forming property of A2017 semi-solid alloys were studied. The results showed that fine and homogeneous non-dendrite microstructures of semi-solid A2017 alloy manufactured by shearing-cooling-rolling (SCR) technology could be obtained and transformed into semi-solid structure which was composed of spherical grains and eutectic liquid through reheating process. The resistance to deformation in semi-solid state decreases as deformation temperature increases or deformation rate decreases. The deformation process of semi-solid A2017 alloy may be divided into four stages. At steady thixotropic deformation stage, the deformation mechanism is liquid flowing, solid particles rotating or sliding, and the thixotropic property is steady. The maximum deformation range is about 60%.