摘要
通过对Ti3Al-Nb电子束焊接接头进行650℃/2h和1000℃/2h的热处理,研究了两种热处理机制的电子束焊接Ti3Al-Nb电子束焊缝组织形态的影响。试验结果发现Ti3Al-Nb电子束焊缝中主要是B2相的柱状晶亚结构,不同的焊后热处理机制的焊缝组织形态差异较大。1000℃/2h热处理后焊缝为α2相和B2相相间的层片状组织(魏氏组织),650℃/2h热处理后焊缝B2相晶界和晶内析出了少量小块状α2相。两种热处理机制都将使接头区域硬度分布趋于均匀化,但1000℃热处理工艺会使接头区域硬度存在某种程度的整体软化现象。
The postweld heat treatment of the electron beam welded joints of Ti3Al-Nb was carried out at 650 ℃ and 1 000 ℃ for 2 hours,respectively.Its effect on the microstructure of electron beam welded joints of Ti3Al was investigated.Experimental results show that the microstructure of the weld under welding conditions is predominantly metastable,the columnar crystal metastructure of B2 phase.The microstructure of the weld is significantly influenced by the method of the heat treatment.The microstructure of the weld for postweld heat treatment at 1 000 ℃ for 2 hours is the laminar structure(Widmanstaten structure)consisted of interphase α2 and B2.After postweld heat treatment at 650 ℃ for 2 hours,the small α2 phase is precipitated in grain boundary and intragranular of B2 phase in the weld.After postweld heat treatment,whether 650 ℃/2 h or 1 000 ℃/2 h,the microhardness distribution of the joints are both more uniform than that of the weld without heat treatment.However,The whole joint is softened after the postweld heat treatment at 1 000 ℃ for 2 hours and the microhardness of the whole joint is not higher than that of postweld heat treatment at 650 ℃ for 2 hours.
出处
《焊接学报》
EI
CAS
CSCD
北大核心
2007年第5期57-60,共4页
Transactions of The China Welding Institution
