Hexagonal Close-Packed

Material Science Volume 1 of 2
Page Navigation
9

Structure of Metals DOE-HDBK-1017/1-93 COMMON LATTICE TYPES In a face-centered cubic (FCC) arrangement of atoms, the unit cell consists of eight atoms at the corners of a cube and one atom at the center of each of the faces of the cube. In a hexagonal close-packed (HCP) arrangement of atoms, the unit cell consists of three layers of atoms. The top and bottom layers contain six atoms at the corners of a hexagon and one atom at the center of each hexagon. The middle layer contains three atoms nestled between the atoms of the top and bottom layers, hence, the name close-packed. Figure 2 Common Lattice Types Most diagrams of the structural cells for the BCC and FCC forms of iron are drawn as though they are of the same size, as shown in Figure 2, but they are not. I n t h e B C C arrangement, the structural cell, which uses only nine atoms, is much smaller. Rev. 0 Page 7 MS-01

Privacy Statement
Press Release
Contact