Evaluation of the residual stresses in 95wt%Al2O3-5wt% SiC wear protection coating using X-Ray diffraction technique

2017 International Conference on Sensors, Materials and Manufacturing

工业技术;材料科学;机械制造

Mahmoud, Adel K.^1 ; Hammoudi, Zaid S.^1 ; Rasheed, Samah^1

Mechanical Engineering Dept., University of Diyala, Iraq^1

关键词: Biaxial stress state;    Diffraction angle;    Isotropic samples;    Mild steel substrates;    Spraying techniques;    X-ray diffraction techniques;    X-ray elastic constant;    X-ray wavelengths;   

Others  :  https://iopscience.iop.org/article/10.1088/1757-899X/311/1/012016/pdf
DOI  :  10.1088/1757-899X/311/1/012016

来源: IOP

【 摘 要 】

This paper aims to measuring the residual stresses practically in wear protection coatings using the sin2ψ method according to X-ray diffraction technique. The wear protection coatings used in this study was composite coating 95wt% Al2O3-5wt% SiC, while bond coat was AlNi alloy produced by using flame spraying technique on the mild steel substrate. The diffraction angle, 2θ, is measured experimentally and then the lattice spacing is calculated from the diffraction angle, and the known X-ray wavelength using Bragg's Law. Once the dspacingvalues are known, they can be plotted versus sin2ψ, (ψ is the tilt angle). In this paper, stress measurement of the samples that exhibit a linear behavior as in the case of a homogenous isotropic sample in a biaxial stress state is included. The plot of dspacingversus sin2ψ is a straight line which slope is proportional to stress. On the other hand, the second set of samples showed oscillatory dspacingversus sin2ψ behaviour. The oscillatory behaviour indicates the presence of inhomogeneous stress distribution. In this case the X-ray elastic constants must be used instead of Young's modulus (E) and Poisson ratio (ν)values. These constants can be obtained from the literature for a given material and reflection combination. The value of the residual stresses for the present coating calculated was compressive stresses (-325.6758MPa).