上清充通大￥ Recovery SHEAMGHAI DUD TONO UHTVEREETTY Subgrain coarsening Consider two adjacent low angle boundaries AB and BC,and let rotation occur in such a direction as to increase the misorientation of the higher angle boundary(AB)and reduce the misorientation of the lower angle boundary (BC). (a) (b) Therefore,if the two boundaries have similar areas,the increase in energy of boundary AB is less than the energy decrease of boundary BC.There is therefore an overall decrease in energy if rotation occurs in such a way as to decrease the misorientation of boundary BC and increase the misorientation of boundary AB,and this will eventually lead to coalescence. Institute of Forming Technology Equipment 21Recovery Institute of Forming Technology & Equipment 21 Subgrain coarsening Therefore, if the two boundaries have similar areas, the increase in energy of boundary AB is less than the energy decrease of boundary BC. There is therefore an overall decrease in energy if rotation occurs in such a way as to decrease the misorientation of boundary BC and increase the misorientation of boundary AB, and this will eventually lead to coalescence. Consider two adjacent low angle boundaries AB and BC, and let rotation occur in such a direction as to increase the misorientation of the higher angle boundary (AB) and reduce the misorientation of the lower angle boundary (BC)