Which one of the following options is correct? In a face-centered cubic metal, Shockley partial is:
FCC Shockley Partial Dislocation Nature
A Shockley partial dislocation is a type of dislocation relevant to crystal structures, particularly the face-centered cubic (FCC) lattice. Its nature is defined by its Burgers vector and its movement capabilities.
Burgers Vector Classification: The Burgers vector represents the magnitude and direction of lattice distortion caused by a dislocation. A perfect dislocation has a Burgers vector that is a full lattice translation vector. In contrast, a Shockley partial dislocation in an FCC metal has a Burgers vector that is not a full lattice vector (e.g., <1/6><211>). This makes it an imperfect dislocation.
Mobility: Dislocations can move or glide through the crystal lattice under applied stress, a process crucial for plastic deformation. Shockley partial dislocations are capable of gliding on specific crystallographic planes. In FCC metals, they glide on the {111} planes. Because they can move, they are considered mobile dislocations.
Combining these characteristics:
- Shockley partials have Burgers vectors that are not full lattice vectors, making them imperfect.
- Shockley partials can glide on {111} planes in FCC, making them mobile.
Therefore, a Shockley partial dislocation in an FCC metal is characterized as an imperfect and mobile dislocation.
Important Questions from Defects Dislocation Stress Field Burgers Vector
- Which one of the following dislocation dissociation reactions is feasible in face-centered cubic metals?
- With reference to edge and screw dislocations, which of the following statements is/are CORRECT?
The Burger's vector of a dislocation in a cubic crystal (with lattice parameter a) is $\frac{a}{2}[110]$ and dislocation line is along $[112]$ direction. The angle (in degrees) between the dislocation line and its Burger's vector is _________
- A plastically deformed metal crystal at low temperature exhibits wavy slip line pattern due to
- The c/a ratio of Zn (hcp) is 1.856. Slip at room temperature occurs most easily on which of the following slip systems in Zn:
Note: In hcp metals, the ideal c/a ratio is 1.633.
