Hexagonal close-packed lattice
Hexagonal close-packed lattice is a crystal structure with a hexagonal base and maximum atomic density. It has limited slip systems, which leads to restricted formability at room temperature.
Physicochemical Mechanism of Action
The hexagonal close-packed (hcp) lattice is a hexagonal crystal structure with maximum atomic density. The atoms are arranged in three layers, with each upper layer placed in the gaps of the lower one. This lattice has only two active slip systems, which limits its formability at room temperature.
Metallurgical Relevance & Risks in Welding
Metals with hcp lattice structure like zinc or tungsten graphite are often difficult to form and deform only at high temperatures. During welding, this can lead to stress buildup that may cause cracks or distortion. Furthermore, the lattice is prone to phase transformations that can impair mechanical properties.
Workshop Practice & Action Instructions
When welding metals with hcp lattice structure like zinc or tungsten graphite, it's important to use high temperatures and slow cooling rates. This prevents stress buildup and phase transformations. The cooling rate should be set so that the lattice has enough time to stabilize and maintain mechanical properties.