2018 年 58 巻 4 号 p. 769-775
It is known that the micro-strain in cold worked iron can be evaluated by the classical Williamson-Hall method using the three data of diffraction peaks: {110}, {211} and {220}. It is not clarified that the obtained value gives the true micro-strain or not. In addition, the accuracy of analysis is not so high because the diffraction strength from {220} plane is generally very weak. In this paper, three methods, i.e. classical Williamson-Hall method, Diffraction Young’s Modulus Correction method and Direct Fitting method, ware attempted to reconfirm the reasonability of the classical Williamson-Hall method and to estimate accurate values of the parameter α and the micro-strain ε in the Williamson-Hall equation. The results obtained are as follows: 1) Elastic anisotropy in the Williamson-Hall plots is corrected using the parameter ω which relates to the values of diffraction Young’s modulus. 2) The optimal values of parameter ω can be determined by the Direct Fitting method, which can be used to determine the timely orientation-dependent diffraction Young’s modulus (E*hkl) in cold worked specimens. 3) It was confirmed that the classical Williamson-Hall method can generally give reliable values for the parameter α and the micro-strain ε. 4) No large difference is found for the values of micro-strain ε from the three methods. 5) There is a clear linearity between the micro-strain ε and yield stress in cold rolled iron specimens.
