Which mechanism causes the brittleness in polycrystalline materials?

💡 Explanation

Grain boundary crack nucleation causes brittleness because boundaries act as stress concentration points, initiating cracks. Because grain separation occurs readily, crack readily propagates across rather than allowing plastic deformation or blunting.

• Which outcome occurs when excessive vibrational motion disrupts molecular bonds in polymers?
• Which outcome occurs when increasing the frequency factor constant?
• Which consequence results when mismatch occurs between fluorophore emission/sensor absorption functions?
• Which mechanism limits the efficiency of dye-sensitized solar cells despite efficient molecular light absorption?
• Which consequence results when the Carnot efficiency limit is reached during a refrigeration cycle?
• Which outcome occurs when a dielectric material with high permittivity gets mechanically stressed inside a capacitor?