【摘要】 进行了不同成分、表面状态、相结构、显微组织的Ｆｅ３Ａｌ基合金在真空及空气中的室温拉伸试验，结果表明，与二元Ｆｅ３Ａｌ相比，本研究Ｃｒ、Ｍｏ、Ｔｉ、Ｍｎ、Ｎｉ、Ｓｉ等代位合金元素中，仅有Ｃｒ的添加提高真空室温拉伸伸长率。利用中子衍射方法分别确定了上述各元素原子在ＤＯ３结构Ｆｅ３Ａｌ单胞亚点阵中的占位，计算了异类原子间相互作用能。结果表明，由于Ｃｒ原子主要替代Ａｌ原子的次近邻Ｆｅ原子，ＡｌＣｒ原子对的结合能低于ＦｅＡｌ对，降低次近邻反相畴界能，使交滑移容易进行。变形试样表面滑移线及位错组态、位错反相畴界研究结果都证实了这一点。Ｂ２形变热处理工艺使Ｆｅ３Ａｌ基合金塑性得到进一步提高的原因是具备Ｂ２结构、片层状拉长晶粒及表面氧化膜三要素。更多还原

【Abstract】 Based on the systematic investigation of the room temperature tensile properties of Fe3Al based intermetallic alloy under different surface conditions,phase structures,grain morphologies and in vacuum and air,the experimental results showed that only Cr improved ductility among the additions of Cr,Mo,Ti,Mn,Ni and Si.In order to understand the mechanism of room temperature mechanical properties,the site occupation of these substitutional atoms at sublattice in DO3 type stocichiometric Fe3Al intermetallics was determined by means of neutron difractometry, and the corresponding interaction energy between different atom pairs calculated.Cr atoms substitute for the Fe atoms located at the next nearest neighbor of Al atoms.Since the interaction energy of AlCr pair is lower than that of FeAl pair,the correstponding APB energy decreased and cross slip is activated more frequently. This is confirmed by the investigation of the surface slip lines of deformed samples,dislocation configuration and antiphase boundaries of dislocation move trace. This study also demonstrated that B2 themomechanical treatment significantly increased both the tensile strength and ducitility.The improvement of room temperature mechanical properties by this processing can be attributed to three factors:B2 structure,elongated flattened grains and surface oxidation scales.更多还原