CAJ | 학술논문

通过高温拉伸试验研究Ti-6Al-4V(TC4)合金激光焊缝的纵向超塑性变形行为,采用扫描电镜观察超塑性变形前后焊缝的显微组织.结果表明:TC4钛合金激光焊缝具有良好的超塑性变形能力,在900 ℃、10~(-3) s~(-1)工艺条件下伸长率达到最大值397%;在超塑性变形过程中,原始焊缝的针状马氏体首先转变为片层状的α+β组织,而后片层组织发生再结晶等轴化;随着变形温度升高或应变速率降低,等轴化程度增大.
통과고온랍신시험연구Ti-6Al-4V(TC4)합금격광한봉적종향초소성변형행위,채용소묘전경관찰초소성변형전후한봉적현미조직.결과표명:TC4태합금격광한봉구유량호적초소성변형능력,재900 ℃、10~(-3) s~(-1)공예조건하신장솔체도최대치397%;재초소성변형과정중,원시한봉적침상마씨체수선전변위편층상적α+β조직,이후편층조직발생재결정등축화;수착변형온도승고혹응변속솔강저,등축화정도증대.
The superplastic deformation behavior of laser welded Ti-6Al-4V alloy by hot tensile tests were investigated, and the microstructures of the weld bead before and after superplastic deformation were observed by scanning electron microscopy (SEM). The results show that the laser welded TC4 joint has good superplasticity, and the maximal elongation of 397% is obtained at 900 ℃ and 10~(-3) s~(-1). During the superplastic deformation, the initial acicular martensite transforms into lamellar α+β phases. Then, dynamic recrystallization occurs and the grain expresses equiaxed trend. The equiaxed degree increases with increasing tensile temperature and decreasing strain rate.