Why are magnesium alloys difficult to form at low temperatures?

Magnesium alloys are difficult to form at low temperatures primarily due to the metal's hexagonal close-packed (hcp) crystal structure.12

Unlike metals with more ductile structures, this specific atomic arrangement limits the material's ductility when worked at lower temperatures. Because of these restricted cold-forming capabilities, magnesium alloys are typically processed through hot-working at temperatures ranging from 150 to 400 °C (300 to 750 °F), where the material becomes significantly more workable.21