Point defect structure and its relation to the material properties in B2-type and L21-type intermetallic compounds.

点缺陷是合金在有限温度下固有产生的缺陷，对合金的物理和力学性能有很大影响。本研究的目的是通过X射线衍射和磁测量来确定具有B2和L21(Heusler)有序结构的二元和三元金属间化合物的点缺陷结构和磁性，并进一步通过长程有序(LRO)参数讨论它们之间的关系。研究了B2Co&lt；1-c&Gt；Fe_c(0.4[小于或等于]c[小于或等于]0.6)合金的结构和磁性随成分和淬火温度的变化。得到的晶格常数和平均磁矩表明，在B2相区，淬火温度降低，而在A2相区，它们几乎保持不变。这些行为是根据LRO参数来考虑的。因此，观察到的变化是…更多地被发现由关于LRO参数的平方的线性形式很好地描述。在假定Fe原子的磁矩与相邻的Co原子数成正比的情况下，用Fe原子的磁矩很好地解释了这种线性关系。此外，研究了CoFeE&lt；1-x&Gt；Alx(0[小于等于]x[小于等于]1)三元合金的结构性质和磁行为与成分和淬火温度的关系。在较宽的成分和温度范围内，B2相存在，L21相出现在973K以下的化学计量比成分(Co2FeAl)附近。在B2相区，平均磁矩随x的增加几乎呈线性减小，且随淬火温度的升高而减小，这与Co&lt；1-c&Gt；Fe_c合金相似。另一方面，在L21相区，磁矩没有明显的淬火温度依赖性，与B2相区的磁矩几乎相同。这些趋势表明，Co位上的无序导致了磁矩的降低(B2相)，而Fe和Al位之间的无序对磁矩没有显著影响(L21相)。较少

Point defects are generated intrinsically in alloys at finite temperature and are well established to strongly affect their physical and mechanical properties. Aim of the present research is to determine the point defect structure and the magnetic behavior in binary and ternary intermetallic compounds with B2- and L2_1 (Heusler)-type ordered structure by means of X-ray diffraction and magnetic measurements and further, to discuss correlation between these through the long-range order(LRO) parametersStructural properties and magnetic behavior were studied for B2 Co_<1-c>Fe_c alloys (0.4【less than or equal】c【less than or equal】0.6) as functions of composition and quenching temperature. Obtained lattice constant and the mean magnetic moment, for any compositions, showed a decrease in quenching temperature in the B2-phase region, while they remained almost constant in the A2-phase region. These behaviors were considered in terms of the LRO parameter. As a result, the observed changes were … More found to be well described by a linear form with respect to the square of the LRO parameter. This linear relation was well explained by noting the magnetic moment of Fe atom under assuming that it is proportional to the number of neighboring Co atoms.Furthermore, structural properties and magnetic behavior were studied for ternary CoFe_<1-x>Al_x alloys (0【less than or equal】x【less than or equal】1) as functions of composition and quenching temperature. The B2-phase existed over wide ranges of composition and temperature and the L2_1-phase appeared around the stoichiometric composition (Co_2FeAl) below about 973K. In the B2-phase region, the mean magnetic moment decreased nearly linearly with increase in x. Further, it showed a decrease with increase in quenching temperature, similarly as in the Co_<1-c>Fe_c alloys. On the other hand, in the L2_1-phase region, the magnetic moment showed no remarkable quenching temperature dependence and had nearly the same value as that in the B2-phase. These trends suggest that disordering on the Co-site leads to the decrease in the magnetic moment (B2-phase case), while that between the Fe- and Al-sites does not significantly affect the magnetic moment (L2_1-phase case). Less