摘要
在室温下,工业纯钛TA2的主要塑性变形方式包括位错滑移、孪生及界面作用。本工作结合辊弯成形实验过程中的力学分析,通过电子背散射衍射和光学显微镜分析了辊弯成形由0°至30°弯曲截面内外侧的微观变形机制。结果显示:辊弯成形0°至10°过程中,内外侧主要塑性变形方式均为〈a+c〉锥面滑移,而〈a〉基底滑移为协调变形方式,位错密度随变形量增加而增大,位错亚晶界含量升高;10°成形至20°过程中,内侧塑性变形机理逐渐转变为以{1022}拉伸孪晶为主的孪生变形,同时,由于弯角区外侧在〈c〉轴方向受压,但{1122}压缩孪晶的临界分切应力较高,主要变形机制仍为位错滑移,以{1122}压缩孪晶为主的孪生变形成为协调变形方式,内外侧可移动位错密度接近饱和,位错亚晶界含量大幅度增加;继续成形至30°时,内侧孪晶密度大幅增加,而外侧孪晶密度缓慢增长,位错之间相互作用加剧,可移动位错密度下降,位错亚晶界含量降低,位错滑移阻力减小,但变形机制未发生改变。这些发现为理解TA2在辊弯成形过程中的塑性变形行为提供了重要的依据。
At room temperature,the predominant plastic deformation mechanisms in industrial pure titanium TA2 encompass dislocation slip,twinning,and interfacial interactions.This study combines mechanical analysis performed during roll-forming experiments and utilizes electron backscatter diffraction and optical microscopy to investigate the microscale deformation mechanisms on both the inner and outer surfaces of TA2 sheets during roll forming from 0°to 30°.The research results demonstrate that during the forming process,as the bending angle reaches 20°,a differential stress is exerted on the axis of the hexagonal close-packed structure on the inner and outer sides.On the inner side,the plastic deformation mechanism shifts from the previously dominant pyramidal slip and basal slip to mainly{1012}tension twinning,which is due to the distinct stress acting on the axis.On the outer side,where the axis is under compressive stress,dislocation slip remains the primary deformation mechanism because the occurrence of{1122}compression twinning is hindered by its high critical resolved shear stress and the fine-grained nature of the material.As a result,{1122}compression twinning functions as an auxiliary deformation mechanism on the outer side.These findings offer critical insights into the plastic deformation behavior of TA2 during the roll-forming process.
作者
李超
韩飞
LI Chao;HAN Fei(School of Mechanical and Materials Engineering,North China University of Technology,Beijing 100144,China)
出处
《材料工程》
北大核心
2026年第3期191-200,共10页
Journal of Materials Engineering
基金
北京市自然科学基金-市教委联合资助项目(KZ201910009011)
北京市属高校高水平教师队伍建设长城学者培养计划(CIT&TCD20190306)
北方工业大学毓杰团队支持计划(107051360023XN075-11)
北方工业大学有组织科研项目(110051360023XN278-10)
国家自然科学基金项目(51074204)。
关键词
辊弯成形
塑性变形机制
孪晶
位错滑移
位错密度
roll forming
plastic deformation mechanism
twinning
dislocation slip
dislocation density
