Does HCP have slip planes?

The h.c.p structure has only two independent slip systems, since any slip on [110](001) can be described entirely as a combination of slip on [100](001) and [010](001). Hexagonal close packed crystals slip on <100>{001} slip systems. This diagram shows a 2×2 array of unit cells projected onto the (001) plane.

What is basal dislocation?

2.2. In other words, basal dislocations find ‘wiggly’ low-energy valleys in which to reside between solute atoms, while the stress rises to a sufficiently high level to push the dislocation past and pull it away from the weak pinning points represented by the solute atoms.

What is twinning plane for HCP crystals?

Explanation: In HCP crystals, twinning plane is {1 0 1 2}. Twinning occurs on these planes. {0 0 0 1} are slip planes. 7.

What are the slip planes and directions in fcc bcc and HCP crystals?

FCC has 12 slip planes with 4 closest packed planes {111} and 3 closest packed directions per plane <110>. HCP has only 3 slip systems. BCC does not have truly closest packed planes so slip must be thermally activated in BCC metals.

What are the 12 slip systems in BCC?

Thus, a slip system in bcc requires heat to activate. Some bcc materials (e.g. α-Fe) can contain up to 48 slip systems. There are six slip planes of type {110}, each with two <111> directions (12 systems). There are 24 {123} and 12 {112} planes each with one <111> direction (36 systems, for a total of 48).

What is twining in crystallography?

twinning, in crystallography, regular intergrowth of two or more crystal grains so that each grain is a reflected image of its neighbour or is rotated with respect to it. Other grains added to the twin form crystals that often appear symmetrically joined, sometimes in a starlike or crosslike shape.

What is a spinel twin?

Form of contact twinning, in which two octahedral crystals twin at the base. Named after the mineral Spinel, which often exhibits this form of twinning.

Why FCC metals are more ductile than BCC and HCP?

The motion of dislocation is the easiest in the closely packed planes, in the closed packed directions; together known as the slip system. FCC has 12 slip systems, whereas HCP has 3 slip systems. This leads to FCC being more ductile than HCP.

What are the 48 slip systems in BCC?

How many 111 planes are in the FCC?

FCC slip occurs on close-packed planes in close-packed directions. There are 4 octahedral planes, (111), (111), (111), and (111), six <110> directions, each one common to two octahedral planes, giving 12 slip systems.

What are the common plastic deformation mechanisms in hcp metals?

In hcp metals, the most popular plastic deformation mechanisms are slip and twinning. In general, slip is always along the lattice close-packed direction on the close-packed plane. Thus in hcp metals, slip system varies with the change of the c/a ratio. For example, basal slip is most easily activated in hcp Mg [1].

What are the different types of dislocation in geology?

The dislocation is in orange (including basal dislocation (BD ), basal stacking fault (BSF), prismatic dislocation (PrD ), pyramidal dislocation (PyD ), shear band (SB), and the cross-slip of PrD and PyD ).

Why do basal slips dominate the initial plastic deformation?

With the increase of θ or β, the Schmid factor of basal slip becomes larger, thus basal slips gradually dominate the initial plastic deformation.