【作者】 辛伟；

【导师】 孙振国；

【作者基本信息】 江苏科技大学 ， 材料学， 2010， 硕士

【摘要】 原子的性质主要由外层价电子结构所决定,当大量的原子聚合成合金(材料)时,合金的性质也将主要由凝聚态原子的价电子结构所决定。余氏理论(The Empirical Electron Theory of Solids and Molecules,简称EET理论)的创立为合金价电子结构的计算提供了理论方法,使从理论上对合金进行成分设计成为可能。铁碳合金作为主要金属用材,在各个行业得到了广泛的应用,并具有其不可替代性。因此研究铁碳合金的价电子结构对于新型优良性能钢铁材料的研制有着重要指导作用。本文以余氏固体与分子经验电子理论(EET)和程氏改进的TFD理论(Improved Thomas-Fermi-Dirac theory)为指导,应用平面价电子结构的计算方法和原子状态判定因子w,在研究铁碳合金基础上,深入研究了二元合金奥氏体与合金马氏体中各原子的杂化状态。当合金中存在异相界面且按一定的位向关系相匹配时,原子的定态除了要考虑键距差|ΔD|的大小之外,同样要考虑界面相对电子密度差Δρ的大小。本文所采用原子状态判定因子w综合考虑了这两种因素的影响,以键距差和相对电子密度差计算方法为基础编写VC++程序,实现了对各元素杂阶的扫描计算,并利用计算所得的信息从价电子结构的角度研究并确定了Fe-C-Mx-My合金奥氏体和Fe-C-Mx-My合金马氏体的价电子结构,界面电子结构及晶胞中原子的杂化状态。在Fe-C-Mx-My合金奥氏体的研究中,通过分析Fe-C奥氏体(111)晶面和Fe-C-Mx-My合金奥氏体(111)晶面的价电子结构,应用原子杂化状态判定因子w来确定合金奥氏体中原子的杂化状态。结果表明:在Fe-C-Cr-Ni晶胞中,Fec、Fef、Cr、Ni的杂化状态分别为B14、B15(或B16)、A7(或A8或A6)和B10(或B11)阶;在Fe-C-Cu-Cr晶胞中,Fec、Fef、Cu、Cr原子的杂化状态分别为B15、B16、B8(或B10或B9)和A7(或A8或A6)阶;在Fe-C-Ni-Mn晶胞中,Fec、Fef、Ni、Mn原子的杂化状态分别为B14、B15(或B16)、B8(或B10或B11)和C11(或C12)阶;在Fe-C-V-Mn晶胞中,Fec、Fef、V、Mn原子的杂化状态分别为B15、B16(或B17)、C12(或C13或14)和C11阶;在Fe-C-Mo-Cr晶胞中,Fec、Fef、Mo、Cr原子的杂化状态分别为B16、B17(或B18)、C5(或C6)和A10(或A11)阶。在Fe-C-Mx-My合金马氏体原子杂化状态的研究中,根据奥氏体向马氏体转变过程中,新相马氏体的(110)面平行于母相奥氏体的(111)晶面,即存在着(111)γ//(110)α位向关系,通过分析Fe-C-Mx-My合金奥氏体(111)晶面和Fe-C-Mx-My合金马氏体(110)晶面的价电子结构,应用原子杂化状态判定因子w确定合金马氏体中原子的杂化状态。结果表明:在Fe-C-Cr-Ni晶胞中,FeⅡ、FeⅢ、Cr、Ni的杂化状态分别为A15、A13、A14(或A15)和A14(或A15)阶;在Fe-C-Cu-Cr晶胞中,FeⅡ、FeⅢ、Cu、Cr原子的杂化状态分别为A15、A14、A16(或A17或A18)和A15阶;在Fe-C-Ni-Mn晶胞中,FeⅡ、FeⅢ、Ni、Mn原子的杂化状态分别为A14(或A13)、A11(或A12)、A11(或A10)和A5(或A6或A7)阶。更多还原

【Abstract】 As atoms’s nature mainly depends on its outer layer valence electron structure, when a large number of atoms aggregate into the alloy (materials), alloy’s nature is mainly determined by the valence electron structure of condensed atoms. Yu’s theory provides a theoretical approach of calculating alloys valence electron structure,which makes theoretically alloy composition design become possible. Meanwhile iron-carbon alloy material as the main metal used in various industries has been widely used and has its irreplaceable. Therefore, research on valence electronic structure of iron-carbon alloy has an important guiding role in the developing new types of excellent performance of steels.In this paper, regarding Yu’s empirical electron theory of solid and molecule, (EET) and Cheng’s improved TFD theory as the guidance, by applying the calculation methods of plane valence electron structure and atom state ascertainment factor w , based on the research of Unary iron-carbon alloy, hybrid states of the atoms in binary alloy of austenite and martensite were investigated. For the definite state of atoms in alloy if exiting biphase interface and arranging by definite phase relationship, the value of bond length difference (BLD)ΔD and relative electron density differenceΔρshouble be both considered. The effect of this two factors is considered simultaneousely as that of atom state ascertainment factor w used in this paper. According to the“Bond-Length Difference Method”and the calculational method of relative electron density difference, VC++ language program has been completed to scan all the involved elements. Through the information obtained by running the program, valence electron structure、interface electron structures and hybrid state of the atoms in crystal units of the Fe-C-Mx-My alloyed austenite and the Fe-C-Mx-My alloyed martensite have been studied and determined.For studying Fe-C-Mx-My alloyed austenite, valence electron structure of the (111) plane of Fe-C alloyed austenite and the one of the (111) plane of Fe-C-Mx-My alloyed austenite are analyzed. The factor w is applied to ascertain the hybrid states of atoms in the crystal cell of alloying austenite. The results indicateded that the hybridization states of Fec、Fef、Cr and Ni atoms in Fe-C-Cr-Ni crystal cell are B14、B15(orB16)、A7(or A8 or A6) and B10(or B11) respectively; Those of Fec、Fef、Cu and Cr atoms in Fe-C-Cu-Cr crystal cell are B14、B16、B8(or B9 or B10) and A7(or A8 or A6) respectively; Those of Fec、Fef、Ni and Mn atoms in Fe-C-Ni-Mn crystal cell are B14、B15(orB16)、B8(or B10 or B11) and C11(or C12) respectively; Those of Fec、Fef、V and Mn atoms in Fe-C-V-Mn crystal cell are B15、B16(orB17)、C12(or C13 or C14) and C11 respectively; Those of Fec、Fef、Mo and Cr atoms in Fe-C-Mo-Cr crystal cell are B16、B16 (or B17 or B18)、C5(or C6) and A10(or A11) respectively.For studying the hybrid states of atoms of Fe-C-Mx-My alloyed martensite, according to the transformation from austenite to martensite, it exists the definite orientation relationship, i.e. (111)γ//(110)α. Valence electron structure of the (111) plane of Fe-C-Mx-My alloyed austenite and the one of the (110) plane of Fe-C-Mx-My alloyed martensite are analyzed. The factor w is applied to ascertain the hybrid state of atoms in the crystal cell of alloyed martensite. The results indicateded that the hybridization states of FeⅡ、FeⅢ、Cr and Ni atoms in Fe-C-Cr-Ni crystal cell are A15、A13、A14(or A15) and A14(or A15) respectively; Those of FeⅡ、FeⅢ、Cu and Cr atoms in Fe-C-Cu-Cr crystal cell are A15、A14、A16(or A17 or A18) and A15 respectively; Those of FeⅡ、FeⅢ、Ni and Mn atoms in Fe-C-Ni-Mn crystal cell are A14(or A13)、A11(or A12)、A11(or A10) and A5(or A6 or A7) respectively.更多还原