In this study, an application of the two-dimensional imaging technology to the X ray tri-axial stress analysis was studied. An image plate (IP) was used to obtain a Debye-Scherre ring and the image data was analized for determining stress. A new principle for stress analysis which is suitable to two-dimensional imaging data was used. For the verification of this two-dimensional imaging type X-ray stress measurement method, an experiment was conducted using a ferritic steel sample which was processed with a surface grinder. Tri-axial stress analysis was conducted to evaluate the sample. The conventional method for X-ray tri-axial stress analysis proposed by Dolle and Hauk was used to evaluate residual stress in order to compare with the present method. As a result, it was confirmed that a sufficiently highly precise and high-speed stress measurement was enabled with the two-dimensional imaging technology compared with the conventional method.

The residual stress measurement by the conventional X-ray diffraction was formulated on the assumption that a specimen from polycrystalline materials was quasi-isotropic and homogeneous, and the stress was biaxial and almost constant within the X-ray penetration depth. Therefore, it was not available to analyze the stress state of the textured materials by the conventional measurement as a general rule. In resent years, advanced methods have been proposed for the X-ray stress measurement of textured materials. In some methods, it is assumed that the X-ray elastic constant is derived from the crystallite orientation distribution function of textured materials for solving the first anisotropic problem. However, there is a nonlinear problem in the stress analysis from the measured lattice strain. In present study, the X-ray elastic constants were averaged as the expected value around the normal direction of the X-ray diffraction in a similar way. A stress analysis was proposed by differential calculus of the X-ray elastic constant in order to the avoidance of nonlinear problem. The stress analysis was applied to residual stress measurements of a titanium carbide coating film with preferred orientation and a cold-rolled steel with texture. The calculated values of the X-ray elastic constants showed the linearity on some condition for the film. The X-ray stress determination was carried out by the fitting the gradients of the measured lattice strain.

The purpose of this study is to examine the effect of crystallite preferred orientation on the mechanical strength of TiCN thin films in highly compressive residual stress. TiCN thin films were deposited by PVD on JIS-SKH55 (AISI M35) steel. The applied substrate bias voltages were set for -50, -80, -100, -120 and -150V. Subsequently, residual stress and crystalline preferred orientation of these specimens were investigated by X-ray diffraction methodology. The crystalline preferred orientation in thin films was evaluated by the ODF calculated from pole figures. On the other hand, dynamic hardness test (DH) and scratch test were executed to evaluate the mechanical strength of thin films. In our study, it was observed that negative bias voltages had an effect on the preferred orientation. The orientation density at -120V was the highest of all specimens. In addition, the value of scratch section area at -120V was the largest of all specimens. As a conclusion, the relation between the scratch area and the negative bias voltages corresponded to the relation between the preferred orientation and the bias voltages.

The purpose of this study is to examine the effect of crystallite preferred orientation on the mechanical strength of TiCN thin films in highly compressive residual stress. TiCN thin films were deposited by PVD on JIS-SKH55 (AISI M35) steel. The applied substrate bias voltages were set for –50, -80, -100, -120 and –150V. Subsequently, residual stress and crystalline preferred orientation of these specimens were investigated by X-ray diffraction methodology. The crystalline preferred orientation in thin films was evaluated by the ODF calculated from pole figures. On the other hand, dynamic hardness test (DH) and scratch test were executed to evaluate the mechanical strength of thin films. In our study, it was observed that negative bias voltages had an effect on the preferred orientation. The orientation density at –120V was the highest of all specimens. In addition, the value of scratch section area at –120V was the largest of all specimens. As a conclusion, the relation between the scratch area and the negative bias voltages corresponded to the relation between the preferred orientation and the bias voltages.

The X-ray stress measurement is an effective method of nondestructive inspection for the residual stress in the surface layer of steel materials. However, the sin2ψ method, which is commonly used as X-ray stress measurement, is inapplicable to such anisotropic materials as textured materials because the theory supposes isotropic elastic polycrystalline materials as sample.The applicable X-ray stress measurement to textured materials was investigated on the assumption that information about each crystallite orientation was deduced by crystallite orientation distribution (ODF). Applied to measure the stress of the titanium carbide nitride (TiCN) film with the ‹111› preferred orientation, the residual stress value was determined from the measured lattice strain. The strong compressive stress value was observed in the film. Compared with methods of other models, the result indicated a small difference from the ‹111› ideal fiber texture model and was situated between the texture model and sin2ψ method.

It is reported that deposited TiN thin films have preferred orientation in recently years. Those films have the fiber texture structure. However, TiN thin films having [111] fiber texture near the single crystal structure by physical vapor deposition was treated in this study. There is no procedure to evaluate the stress-strain state for such sample. Therefore, a new procedure of X-ray stress measurement for single crystal having [111] fiber texture is proposed. In addition, the procedure is compared with precedent procedure up to present. The crystallite orientation was evaluated by the pole figure, and the residual stress was measured using Cu-Kα radiation with three methods. METHOD1 is the model of polycrystals, METHOD2 is the model of single crystal and METHOD3 is the way used a convenient measurement technique that is proposed by Tanaka et al. for single crystal. As a result, the stress using the single crystal model and using the polycrystals model had similar value. In METHOD3, the value between σ_<11> and σ_<22> made a little difference.

Difficulties often attended determining the residual stress of cold-rolled steel sheets with crystallographic textures from the conventional X-ray stress measurement, i.e., the sin* d, technique, because the technique is constructed on assumption that specimens are isotropic elastic polycrystalline materials. Therefore, the aim of this investigation is to develop an effective X-ray stress measurement for textured materials. At first, the relation between the stress and lattice strain measured by the X-ray diffraction is formulated by an average method. In the method, the strain is averaged as the expected value with a weight function from the crystallite orientation distribution function (ODF). Then, in order to lower the effect on the unstressed lattice spacing, an X-ray stress determination is introduced by using the derivative of the X-ray stress-strain relation. Moreover, the X-ray stress measurement is actually applied to cold-rolled steel sheets, and the stresses are determined.

Sintered high chromium steel containing titanium nitride has high wear-resistance and heatresistance. This material is used in practice for valve seats, which are one of the parts in diesel engines for automobiles. The purpose of this study is to carry out a fundamental investigation on an application of the method of x-ray stress measurement to this material in order to make clear the state of residuakstress and to evaluate the material strength. As this material consists of two constituents (phases), the stresses in each phases (so-called phase stresses) are expected to be different from each other. The material has also some pores due to the manufacturing process of powder metallurgy. Therefore, its x-ray elastic constants differ from those in single phase state due to the disturbance of the state of stress caused by the existence of the second phase and the pores. As the x-ray elastic constants are important for the x-ray stress measurement, it is necessary to make clear such influence. From the point of view mentioned above, a theoretical analysis was carried out in this study as the first step in the investigation of the influence of the volume fraction of the second phase (titanium nitride) on the composite x-ray elastic constants (CXEC) of this material. The micromechanics approach developed by Lin and Mura, which is called the Eshelby/Mori-Tanaka model in this study, was used for analyzing phase stresses in each phase. The relation between the x-ray elastic constants and the volume fraction of titanium nitride was calculated in this manner for both 211 diffraction of the matrix and 420 diffraction of the second phase. The result was compared to those calculated according to the Voigt model, the Reuss model and the self-consistent model respectively, as well as those obtained experimentally.

The commonly used X-ray stress measurement, so-called sin2Ψ method, is valid for the stress determination from the X-ray diffraction data. However, the method fails if the samples are anisotropic because the method is constructed from some assumptions, one of which is that the samples are regarded as isotropic and homogeneous polycrystalline materials. Therefore, in order to be applicable the polycrystalline materials with ‹HKL› preferred orientation, the method was improved by the introduction of the rotation symmetry about the normal axis to the X-ray diffraction plane in this paper. The basic equation in the X-ray stress measurement i.e. the X-ray stress - lattice strain relation was derived for ‹HKL› preferred orientation in result. Then, the method applied to a centrifugal casting part, and was discussed in comparison with the sin2Ψ method.

In this study, we investigate the residual stress of titanium carbide films with the X-ray diffraction method. It is difficult to determine the stress by conventional X-ray stress measurement, i.e., the sin(2)psi technique, because the sin(2)psi technique requires macroscopic isotropy from the specimen but the <110> orientation is observed for our evaporated TiC films by chemical vapor deposition. Therefore, in this paper, the X-ray stress measurement for <110>-oriented films was formulated by introducing the weighted average method. The formulation showed that the relation between the stress of the specimen and the strain measured by X-ray diffraction depended on the measured diffraction planes. Then, a stress calculation was performed and discussed based on the loading experiments.