摘要
TiAl合金和Ti合金由于缺少滑移系,是典型的难变形材料.本文探索应用高密度脉冲电流改善其成形性.所选择的材料是TiAl合金(Ti2AlNb)、TC4合金(Ti-6Al-4V)、TA15合金和TA1-A.研究了脉冲电流处理对变形损伤的影响,研究结果表明,在一定条件下因塑性变形而产生的微裂纹可以被治愈,并形成局部的再结晶组织,预塑性变形试样的塑性可以被完全恢复,极限变形量得到提高.对退火态的板材进行了高密度电流脉冲处理试验分析,试验结果表明,电流脉冲处理显著地改变了板材的力学性能:均匀延伸率提高、屈服应力和屈强比下降.这对改善钛合金板材成形性具有重要的意义.选用冷轧态板材进行了脉冲电流处理实验,研究结果表明,脉冲电流处理可以大幅度地提高冷轧钛合金板材的塑性,同时材料强度不降低,由于晶粒的细化作用,强韧性得到改善.本文的研究结果表明高密度脉冲电流是改善难变形合金成形性的一种有效方法.
The present work aims at improvement in formability of difficult-to-work alloys through high density electropulsing. The selected materials are TiA1 alloy （Ti2A1Nb）, TC4 （Ti - 6Al - 4V）, TA15 and TA1 -A. The effect of electropulsing on damage evolution of sheet metal is investigated. Experimental results indicate that the plasticity of the specimens with 8% of pre-plastic deformation is nearly recovered completely by electropulsing treatment, and the forming limit is increased. Microcracks resulted from plastic deformation are healed, the local recrystallization occurs in the sheet metal after the electropulsing treatment. An annealed sheet is treated by high density electropulsing under ambient conditions. The experimental results indicate that the electropulsing treatment significantly changes mechanical property of sheet metal. The uniform elongation is increased and the yield stress and yield to tensile ratio are decreased. The electropulsing gives a significant increase in elongation of cold-rolled titanium alloy sheet, but the tensile strength is not decreased.
出处
《材料科学与工艺》
EI
CAS
CSCD
北大核心
2013年第5期117-124,共8页
Materials Science and Technology
基金
国家自然科学基金资助项目(50875061)
教育部高等学校博士学科点专项科研基金(20092302110016)
关键词
难变形合金
脉冲电流处理
力学性能
损伤治愈
晶粒细化
difficult-to-work alloys
electropulsing
mechanical properties
healing damage
grain refinement
