摘要
利用自行研制的旋转盘式杆杆型冲击拉作试验装里对Fe3Al实施了不同应交率的冲击拉伸试验，获得了不同应变单下的完整的应力应变曲线．结果表明在应变率从80S-1至1200S-1范围内，Fe3Al存在明显的动态韧性现象及应变率强化效应，其屈服应力、破坏应力以及破坏应变都随应变率的提高而增加．用最小二乘法拟合得到其屈服应力、破坏应力以及失稳应变与应变率的关系，并根据Bondner-Partom的理论建立了Fe3Al冲击拉伸加载条件下的一线无屈服本构模型．SEM观察结果表明，室温下Fe3Al的断裂方式主要表现为穿晶解理断裂，影响其破坏的主要因素是氢脆（环境脆性）．观察发现，高应变率下其断口处出现明显的晶粒细化现象．高应变率抑制了空气中水汽对Fe3Al的环境腐蚀，提高了Fe3Al的变形能力，导致动态韧性．同时，还验证了H2O可加速氢脆的进程，并对上述现象进行了解释．
The loading tests of Fe3Al under tensile and impact have 'been carried out on aself-designed rotating circular disk tensile and impaCt apparatus. An experimental studyof Fe3Al was performed at the strain rate ranging from 80s-1 to 1200s-1 and complete stress-straincurves are abtained for Fe3Al under tensile and impact. It can be seen from theresults,that Fe3Al obviously has dynamic ductility and effect of strain-rate hardening. The yielyield strength, the ultimate strength and the failure strain increase with the increasing ofstrain rate. From the linear least-squares fit, the relationship the relationship between the yieldstrength, the ultimate strength, the failure strain and strain rate are obtained under tensileadand impact. At the same time, we derived onedimensional rnacroconstitutive equation for Fe3Alunder tensile impact according to the elastic-viscoplastic constitute theory. At room temperature,the observation of the fracture surface on SEM showed that the dodrinant fracture process inthe formation of transgranular cheavage and grain4oundary cracks. The ma or factor of failureon Fe3AJ is hydrogen embrittlement. We observed that the grain size on the fracture surfacedecreases at higher strain rates. In addition, we proved that water can improve the pr0cess ofhydrogen embrittlement.
出处
《材料科学与工艺》
EI
CAS
CSCD
1998年第4期1-5,共5页
Materials Science and Technology
基金
国家自然科学基金
