文档介绍：材料科学基础 Fundamental of Materials Lesson fourteen Lesson fourteen § Rotation of Crystal during Slip ?Ⅰ.The cause of rotation: Due to constraints, or boundary conditions, imposed on the crystal. ?Ⅱ.The rule of rotation : 1) axis of rotation ∥∥ R ?R ?lL ???lb ??? bnllL ?????)(??? 2) During slip, the . tends to approach to loading direction in tension. During slip, the . tends to approach pression plane pression. F F FF FF F F ?Ⅲ.The consequence of rotation : 1. Change in length of the specimen ????? 22 cos cos cos 21???lL① In tension bnllL ??????)(???????? cos cos sin sin 00l L b ?? n ??② pression nbaaA ??????)(????② Geometrical softening in tension Schmid ’ s law at the onset of slip: ???? cos cos ? const. ?? C?? ooy??? cos cos ? o oo oA FA F????? cos cos ) cos ( cos ?????????? o C???? cos cos ? 2. Change in orientation 2. Change in orientation ① Orientation change and multislip Example: Example: Given: Given: a FCC crystal held in tension a FCC crystal held in tension ∥ Determine Determine : : 1. Single slip system 1. Single slip system 2. Rule of rotation 2. Rule of rotation 3. and orientation at the onset of duplex of slip 3. and orientation at the onset of duplex of slip 4. Rule of rotation during duplex slip 4. Rule of rotation during duplex slip 5. Final orientation, . the state position 5. Final orientation, . the state position F ?]521 [ ? 1. slip system: 2. locus: F tend to , ∥∥ 3. ]110 )[ 111(]110[]110[?FR ??] 211 [R ?2 ]110[3 ] 111[]512[ )(??????bnl bnllL?????????6 6 6261202 ]110[6]512[ 2 ]110[)3 ] 111[]512 ([]512[][ ][ let?????????????????????w vu uvw uvw l?????]311[ //]622[ //F ??]01 1 )[111(]110 )[ 11 1(: systems slip duplex ? Solution: 4. 5. stable: ]011[ 21???RRR ???][:wvuF ????]110[][]01 1[][ 2 1???????