Grain　boundary　plane　distributions　have　been　measured　for　Sigma　2　grain　boundaries　(boundaries　that　have　a　90　degree　rotation　about　the　[10-10]　axis)　in　undeformed　and　plastically　deformed　WC-Co　cemented　carbides.　By　virtue　of　electron　backscattered　diffraction　data　coupled　with　the　five　parameter　analysis　method,　the　measurements　show　that　while　the　misorientations　of　the　Sigma　2　boundaries　are　20%　reduced　by　the　plastic　deformation,　there　are　33%　reduction　in　the　orientation　of　the　Sigma　2　twist　grain　boundary　plane.　A　dislocation　model　for　grain　boundary　plane　reorientation　during　plastic　deformation　is　proposed.　(C)　2014　Elsevier　Ltd.　All　rights　reserved.