Fig.3 The microstructure of the other G.S.and SAD patterns. (a)BF imagc of ithe fan-like arca.(b)-(f).SAD diffractions from Ictters A,B,C,D and I positions in (a). In order to examine the structure and crystallgraphic orientation of the platelets in the G.S.a series of SAD at the interesting positions marking A,B,C,D and I were carried ont as shown in Fig.3a and Fig.3b-3f,respectively.At the both sides of ihe interface marking letter I,the C001]direction of the platelets are approximateiy parallel to the radial of the G.S.though there are small mi- sorientation among the platelets each other (see Fig.3b,002*diffraction spot extended to an arc). The formation mechanism of G.S.and the effect of Ce addition on growing of graphites could be proposed from present results by TEM. The {001}planes of graphite are closest packing planes,[001]is not a close packing direction.Reviewing the morphologies and the size of the platelets,it is clear that the growing rate of (001)plane is much bigger than the 001]direction (see Fig.2b and Fig.3a).It implies that the preferred growing of the graphites do still influence the morphologies of G.S.As a matter of fact,{001}planes are quite developed than the others (see Fig.2b).It was only due to Ce-addition that the anisotropy of the graphites was restrained during the growth of G.S.In addition,as Hunter and Chadwick ,a)suggested that the first growth is in flake form or as the present observations it is adherence to a nucleus of cerium oxide or cerium Oxysulfide if possible.Furthermore,it showed that growth branching of graphites has paid an important role in formation of G.S.otherwise the graphites in cast irons could not grow up a spherulitc.Finally,from the morpho- logies and crystallgraphic characterization of thre G.S.as shown in Fig.3,they are the projection of two reciprocal pyramids formed in helical growing or conical helixes in the both sides of the interface I,as is proposed by Double and Hallawellt.And the {001 crystallgraphic plancs of a graphile pyramid have 583一 片 卜 · · 一 一 ， ， 注 · ， ， ， · · 一 ， · ， ， 〔 〕 · ， 。 一 · ， 〔 〕 一 ， 〔 〕 · · 一 · ， 一 一 · · ， ” 一 ， · ， · 一 · ， ， 了 一 ‘ 」 ， 、 、