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为了发展大直径薄壁纯钛管数控加热弯曲技术,实验研究了大口径薄壁CP-3管材在不同温度下数控弯曲后的内外侧塑性变形机制。通过EBSD分析和维氏显微硬度测试方法,对数控弯曲温度293、423和573 K下弯管件试样弯曲外侧受拉区域以及弯曲内侧受压区域进行显微组织变化和维氏硬度分析。结果表明:1)在不同温度下数控弯曲变形后,弯管外侧塑性变形机制主要为滑移,孪生变形微弱,择优取向类似于初始管材的;弯管内侧塑性变形机制主要以{1 012}孪晶为主,滑移为辅助机制,且孪晶使管壁材料择优取向产生剧烈转变。2)维氏硬度的变化与塑性变形机制及织构有关。弯曲变形后,管材试样内外侧轴向与周向的维氏硬度值均显著得到提高,且管材试样内侧的维氏硬度值要明显高于外侧的,周向的维氏硬度值高于轴向的。
In order to develop a large-diameter thin-walled titanium tube CNC heating bending technology, experimental study of large-diameter thin-walled CP-3 pipe at different temperatures after the numerical control of plastic deformation inside and outside the plastic deformation mechanism. By means of EBSD analysis and Vickers microhardness test, the microstructural changes and Vickers hardness analysis of the flexural area and the medial compression area of curved pipe specimens at 293, 423 and 573 K were carried out. The results show that: 1) After the numerical control bending deformation at different temperatures, the plastic deformation mechanism outside the elbow is mainly slip, the twins are weakly deformed and the preferred orientation is similar to that of the initial pipe. The plastic deformation mechanism inside the elbow mainly takes {1 012} Crystal-based, slip as a secondary mechanism, and twin to the wall material preferred orientation have a dramatic change. 2) Vickers hardness changes and plastic deformation mechanism and texture. After bending deformation, the Vickers hardness values of both the axial direction and the circumferential direction of the pipe specimen are significantly improved, and the Vickers hardness value inside the pipe specimen is obviously higher than the outside, and the circumferential Vickers hardness value is higher than Axial.