Why does X-ray diffraction analysis on a metal alloy with high concentration of grain boundaries often produce broader, less defined peaks in the diffraction pattern?

💡 Explanation

Grain boundaries disrupt the periodic lattice structure, thereby reducing long-range order. This leads to variations in the interplanar spacing (d-spacing) which broadens the diffraction peaks, because the Bragg diffraction condition is only sharply met for perfect crystals; therefore, grain boundary disorder broadens peaks rather than impurity absorption, size effects, or thermal effects.

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