A study was made of a simulated -Ti grain boundary. It was deduced that the structural unit of the dislocation core has the form of a tetrahedron; separated by perfect regions. This grain boundary could therefore be regarded as being a low-angle boundary. The length and width of the dislocation core were |1/9[5¯4¯10]| and |12/55[12¯30]|, respectively. Each dislocation core corresponded to an edge dislocation with a Burgers vector of 12/55[12¯30](|1/3[11¯20]|) and existed as 2 Shockley partials. It was noted that the structure of the dislocation core was unique, and that this grain boundary was a favored one in hexagonal close-packed metals.

Read-Shockley Dislocation Core Structure of a  = 7 [00•1] 21.8° Grain Boundary in Hexagonal Close-Packed Metals. Y.C.Wang, D.X.Li, H.Q.Ye: Scripta Materialia, 1996, 34[5], 735-9