Prismatic glide

The hardness of WC is associated with the fact that the array of W-atoms in the cores of glide dislocations changes from hexagonal prismatic to quasi-octahedral so the coordination number of the C-atoms changes from approximately six to approximately eight. This increases the local electron density so dislocation motion is resisted. 

Figure 23.4 Prismatic dislocation punching at spherical precipitate, (a) A dislocation dipole loop is generated in the interface. One side expands into the matrix while the other remains in the interface, (b) Segments of the loop in the matrix glide downward to form additional loop length in the interface, (c) The loop in (b), which is partially in the interface and partially in the matrix, pinches together at its lowest point and splits into two loops, with one remaining in the interface and the other gliding into the matrix. From Porter and Easterling [4],...

Begining of the simulation (left), after deformation (right). Basal dislocations glide horizontally (horizontal lines), dislocations in the prismatic plane vertically (white vertical lines). The center of the cylinder is represented. 

Slip Modes in the a-Phase. Various modes of slip can occur in a-Ti or in the a-phase of titanium alloys (see Table 4). In general, slip can occur on prismatic, pyramidal and basal planes by the movement of , [c] and -type dislocations. Since the <1120> slip directions are common to aU three planes, the -type dislocations can ghde on prism, pyramid, and basal planes. The -type slip can take place on prismatic and pyramidal planes. The [c]-type glide is restricted to only prismatic planes and generally does not occur. 

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