【作者】 马海军； 李亚江； S.A.吉拉斯莫夫； 王娟； 孙小磊；

【Author】 MA Hai-jun LI Ya-jiang S.A.Gerasimov WANG Juan SUN Xiao-lei (1.Key Laboratory of Liquid Structure and Heredity of Materials,Ministry of Education,Shandong University,Ji’nan 250061,China;2.Department of Materials Science,Bauman Moscow State Technical University,Moscow 105005,Russia)

【机构】 山东大学材料液态结构及其遗传性教育部重点实验室； 莫斯科鲍曼国立科技大学材料科学系；

【摘要】 Fe₃ Al 金属问化合物具有 B2和 DO₃两种有序结构。焊接条件下,由于冷却速度较快,B2-DO₃的固相转变呈现不完全性。深入研究焊接条件下 B2-DO₃的转变特点及其对 Fe₃Al 焊接性的影响,对于理解 Fe₃Al 的脆性本质及解决 Fe₃Al 的焊接问题具有重要意义。采用透射电镜（TEM）和选区电子衍射（SEDA）方法对焊接条件下 Fe₃Al 的有序转变进行研究。结果表明,熔焊时 B2-DO₃有序结构的转变主要发生在热影响区,并存在两种转变模式: 在位错密度较大处为间隔转变,在位错密度较小处以析出转变为主。间隔转变是 Fe₃Al 焊接时主要的转变模式, 导致 Fe₃Al 的脆性增大易产生裂纹。熔合区中位错环的产生是宏观应力与微观应力共同作用的结果,其存在有利于缓解熔合区的应力集中以及降低裂纹的产生几率。更多还原

【Abstract】 Fe₃Al possesses two ordered structures,B2 and DO₃.Under welding conditions,B2-DO₃ transformation is characterized by incompleteness due to fast cooling rate.To investigate the transformation characteristic and the effect on Fe₃Al weldability is important to understand the essential brittleness and solve fusion welding for Fe₃Al.The ordered transformation was studied via transmission electron microscope （TEM） and selected electron diffraction analysis （SEDA）.The results indicate that B2-DO3 transformation can occur in two models during welding process:alternation transformation model and precipitation transformation model,depending on local dislocation density.Alternation model is major model for B2-DO₃ transformation,which increases the brittleness of heat affected zone （HAZ） to induce cracking.The dislocation loops in fusion zone are induced by the macro-stress and micro-stress,whose existence is favorable to releasing the stress concentration to avoid cracks.更多还原