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Temperature has great influence on the stacking fault energy (SFE). Both SFE and dr0/ d T for Fe-based alloys containing substitutional or interstitial atoms increase with increasing tempera-ture. Based on the thermodynamic model of SFE, the equation dr0/dT=drcn/dT+drseg/dT+drMG/dT and thoseexpressions for three items involved are established. The calculated dr0/dT is generally consistent with the experimental. The influence of chemical free energy on the temperature dependence of SFE is almost constant, and is obviously stronger than that of magnetic and segregation contributions. The magnetic transition and the segregation of alloying elements at stacking faults cause a decrease in SFE of the alloys when temperature increases; that is, drMG/dT<0 and dyseg/dT<0. Meanwhile, such an influence decreases with increasing temperature, except for the drseg/d 7 of Fe-Mn-Si alloys. With these results, the experimenal phenomena that the SFE of Fe-based alloys is not zero at the thermo-dynamically equilibrated tem 相似文献
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The relationship between the electronic structure of FCC phase in Fe-Mn-Si alloy and its stability has been studied by using the discrete variational method based on the first principle. The reason why Mn and Si elements have different influences on the stacking fault energy may be related to the electron concentration ( e/a). Si reduces the hole number of 3d band while Mn is rather complicated . The binding energy has been calculated and the experimental results that martensite start temperature (Ms) varies with Si and Mn are explained. When the external stress is exerted in three directions, the electronic structure, the total density of states, the energy gap at Fermi energy level( EF) and the energy degeneracy will change into other states. When the different external stresses are exerted in one direction, 3d or 4s orbital occupations of the central atom decrease, the partial density of states seems to be thinner and its peak increases at EF, the bond orbit shrinks in the direction of the external st 相似文献
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研究了Ni2Al-XCr、NiAl-XCr二个系列合金的显微组织与结构,并对合金的导电率、维氏硬度和三点弯曲性能进行了测试。本文还就不同Cr含量对合金性能的影响关系以及Ni-Cr-Al合金作为真空断路器(VCB)电极材料的应用前景作了进一步讨论。 相似文献
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巨磁阻抗多层膜相比单层膜具有不可比拟的优越性,它可以在很低的频率范围获得非常明显的巨磁阻抗效应。综述了多层膜GMI效应的研究现状,着重探讨了材料、膜尺寸及绝缘层隔离对多层膜GMI效应的影响,并且探讨了多层膜GMI效应的物理本质。 相似文献
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