Reduction of crystallographic point groups to subgroups by homogeneous stress
1965; The National Institute of Standards and Technology; Volume: 69A; Issue: 4 Linguagem: Inglês
10.6028/jres.069a.032
ISSN2376-5704
Autores Tópico(s)Microstructure and Mechanical Properties of Steels
ResumoIt is.assu med t h at the symmetry operation s possessed b y a homogeneo u sly stressed crystal wIll be t hose common to t he crystal and to t he stress.Application of stress either leaves a point group ur:altered or lowers it to a subgroup .Any stress-induced minimum ~te p of symmetry lowermg can be caused by unaxial stress but t hree of the po ss ible stressmduced compound steps of symmetry lowering require biaxial stress.Th e unia xia l or biaxia l s ~ress required fo r any.s~ress-induce d syn:metry lowerin g is tab ulated a nd stereograms are g.l ven for ea~h .o.f t he ml111mum step s showm g t he relation of t he remaining sy mmetry operat l.ons ~o t he ullt!al symmetry and sholVlIlg the splitting of a set o f init ia lly equiva len t general dU'ectlOns mto m equlvalent subsets.These stereo<Tram s provide a direct representation of t he splitting of a genera l pos ition in a crystal into i'n: qui valent subsets for the symmorphic space groups a n d the latte r a rc Ilsted ; t he effect of gh de planes and screw axes must be considere?~n the remain ing space groups yet .thestereog ra m s still provide t he correct pattern o. f spll ttll1g.V ses of the stereograms, for Jl1 stance, t o obtain t he splitting of [t specia l p osi-~lO n , a re descnbed.
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