(東北大學(xué) 材料與冶金學(xué)院，沈陽(yáng) 110004)
摘 要: 使用DEFORM-3D軟件模擬等通道轉(zhuǎn)角擠壓過(guò)程中外轉(zhuǎn)角半徑及背壓對(duì)純鈦應(yīng)力和應(yīng)變分布的影響，探討不同 R值對(duì)材料流動(dòng)的影響規(guī)律。結(jié)果顯示：當(dāng)R = 6 mm時(shí)，工件上下表面應(yīng)力狀況較為平衡，從而得到均勻的等效應(yīng)變分布；當(dāng)R＜6 mm時(shí)，在外轉(zhuǎn)角形成的死區(qū)使材料之間相互搓動(dòng)，導(dǎo)致工件底部區(qū)域出現(xiàn)劇烈畸變，工件不同區(qū)域之間的等效應(yīng)變量差別較大；當(dāng)R＞6 mm時(shí)，工件上表面與模具內(nèi)轉(zhuǎn)角之間的相互作用力增加，使工件頂部變形加劇并導(dǎo)致工件等效應(yīng)變量不均勻；施加背壓(pb)后，能有效提高等效應(yīng)變量；適當(dāng)?shù)?I>R值與pb匹配可使工件得到均勻的應(yīng)變分布。
關(guān)鍵字: 等通道轉(zhuǎn)角擠壓；外轉(zhuǎn)角半徑；數(shù)值模擬；背壓；純鈦
（School of Materials and Metallurgy, Northeastern University, Shanyang 110004, China）
Abstract:The strain and stress distributions of pure Ti during equal channel angular pressing (ECAP) were simulated by using software of DEFORM-3D with different angular radii and black pressures. The simulated results indicate that the friction forces in the upper and bottom regions can be balanced and the homogeneous equivalent strain distribution can be obtained when R=6 mm. When R＜6 mm, the equivalent strain is non-uniform at the bottom of the workpiece, because the death zone makes the materials interact each other, thus induces the bottom of workpiece acutely distorted and makes the value of equivalent strain vary obviously in different regions of workpiece. At R＞6 mm, the friction force interacts between the upper face of workpiece and inner corner angular of die, which makes the upper of the workpiece deform remarkably and induces non-uniform equivalent strain distribution. The back pressure can increase the value of equivalent strain. Besides, uniform strain distribution can also be obtained by adopting reasonable back pressure and outer angular radius.
Key words: equal channel angular pressing; outer angular radius; numerical simulation; back pressure; pure titanium
