Which mechanism causes increased brittleness in polycrystalline turbine blades when grain boundary segregation of impurities concentrates?

💡 Explanation

Increased impurity segregation at grain boundaries elevates the ductile-brittle transition temperature because cohesive strength decreases due to weakened atomic bonds within the crystal lattice. Therefore, the material fails in a brittle manner at operational temperatures, rather than plastically deforming as intended.

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