出口通道背部摩擦力对工业纯钛室温ECAP变形影响的有限元分析

Effect of friction between the back of the billet and outlet channel on the finite unit analysis of ECAP for CP-Ti at ambient temperatures

工业纯钛的等径弯曲通道变形（EqualChannelAngularPressing，简称ECAP）通常在350～450℃实现，为研究工业纯钛室温ECAP变形的可行性，提高其细化效率，本文利用三维有限元商品软件Marc．Super—form对工业纯钛方形试样的一道次室温ECAP变形过程进行模拟．研究并分析了模具出口通道背面摩擦对工业纯钛（CommercialPureTitanium，cP．Ti）试样变形、应变速率及挤压载荷分布的影响规律．研究表明，增大模具出口通道背部摩擦可使工业纯钛ECAP变形区的应变速率分布更均匀，使试样内应变分布均匀性提高．在此基础上通过改善外部摩察工艺条件成功地实现工业纯钛室温ECAP变形，获得变形均匀的ECAP试样．

All early investigations of equal channel pressing （ECAP） on CP-Ti were carried out in the temperature range of 623-773K. In order to evaluate the feasibility that CP-Ti was processed by ECAP without failure at room temperature, Marc Superform, a 3D finite unit model software, is used to analyze the deformation heterogeneity of commercial pure ti- tanium （CPTi） during equal channel angular pressing （ECAP） for one pass at ambient temperature. The simulation of the total equivalent plastic strains in three perpendicular plans of the deformed billet was carried out and different friction co- efficient between the back of the billet and outlet channel were employed in order to obtain uniform workpiece. This study shows that the strain homogeneity increases and the strain rate is more homogeneous with friction between the back of the billet and outlet channel. And CP-Ti may be processed by ECAP at room temperature through altering the state-of-stress of work piece.