??? ????????? Chapter 5 Deformation and re-crystallization of materials

1
???

• ??? ?????????Chapter 5 Deformation and
  re-crystallization of materials

5.2 ???????
2
5.2 ???????(plastic deformation)

• ??
• ????????,?????????????
• ??????????????,??????,???????????,??????????????
• ??????????
• ????????????
• ??(slip)
• ??(twinning)
• ??(knitting)?

3
1???(Slip)

• ??
• ?????????,?????????????(metallographic
  plane)(???(Slip plane))???????( metallographic
  direction)(????(Slip direction))?????????????????
  ?

4
???(shear stress)???
?????? ????????,??????????(lattice
distortion),?????????????????,?????????????,??????
??????,????????(permanent deformation)????????????
?????,????????????????(step)?
5
???(Normal stress)???

• ????????????????????,?????????????????????
  ,????????
• ??????????????,????,????????
• ?????????,???????????????,????????????????,?
  ???????????????

6
1)???????

• ????????,???????????????????,???????????,?????????
  ?????????????,??????(slipbands)?
• ???????????????, ???????????????,?????(slip
  lines)?

7
2)???(SLIP SYSTEM)

• ???(slip plane)??????????????,??????????(Highest
  Planar Density )?
• ????(slip direction)??????????????,??????????
  (Highest Linear Density)?
• ??????????????????????

FCC (111)Plane lt110gtdirection
8

• ??????????????????
• ??????????

9
????????????????

• ?????????????,???????b??,???????
• FCC???111????110
• ????????½110 ? 001
• ??Frank??,???????????????,?????????????
• ½110??????2a2/4
• 001??????a2?
• ??,?????110?

10

• ??????????

6
lt11-20gt
(0001)
48
????????
BCC 1106lt111gt211212lt111gt112324lt111gt1 48
11
(No Transcript)
12
???????????
13
???????????
?????
?????
?????
???????????????????????????
????-K.H.????,????,??????????,?????,1999
14
?????????

• ??????(?????)(???????????????)
• ????????,?????????????,???????,??,????????????????
  ?????????????
• ??????????48????????????????12????,?????????????
  ?????????,???????3?,???????????????

15
SCHMIDS LAW (?????)
???
Cross section

• 3)?????????
• (Critical resolved shear stress)
• ?-????????F??????
• ?-???????F???
• F?????????Fcos?
• ???????A/cos?

Normal to slip plane
Slip direction
???
Shear area and slip plane
A resolved shear stress
16

• ??????????(Schmid factor) m ?cos?cos??
• ??????? f?,????????
• ???? 90º - f?
• ??f 90º ? ? 90º?,?s????,??????????????????????
  ?????????????
• ?? f45º?,????????1/2,??,???????????.

17

• ?5.9???????????????????????,?????????,??????,??,??
  ?????
• ??????????????????????????????

18
?????????????????????????????,????????????????????
??????????
19

• ??1Mg?????????,3??????????????38,45,85,???????
  ?????60????????2.05 MPa?,?????????,?Mg???????????

• ??Mg?????(0001)??,?
  ??,? ???(60 ) ?,
  ???,t??,???????,????????38 ?????????????????,Mg??
  ?????

20
?????????

• ???????????????
• ?????????????????????????????????????????,????????
  ???,????????????,??????????????????
• ?????????????????????????????????,????????????????
  ??
• ????????????????
• ????????

21
4)????????

• ?????????????,????????????????????????
• ???????????????????????????,???????????????????
• ?????????????????,??????????????

???
??
???
22
??????????????
? ?
?????????????
23
??????????????
?????????
R.C. Zeng et al. / Materials Science and
Engineering A 509 (2009) 17 R. Zeng et al. /
International Journal of Fatigue 32 (2010) 411419
24
????????
(a) Rolling. (b) Forging (open and closed die).
(c) Extrusion (direct and indirect).(d) Wire
drawing. (e) Stamping.
L.L. Chang et al. / Materials Science and
Engineering A 496 (2008) 512516
25
????????????
SSRT ???????
????
?? ??
??
Air
Solutions
26
5)????

• ????
• ????????????????????????,??????

??????????????
27
?????

• ????????????,?????????????????,???????????????????
  ?????,????????????,???????????????????????????
  ???,?????????? ?

???????????
28
????

• ?????????????????????????????
• ??????????????????,???????????????????
• ???????????????

29

• ??????
• ????????,????????????????????????????

30
???????

• ???????????
• ???????????
• ???????????

• ??????
• (a) ??? 100 ,(b)??? 100 , (c)??? 200

31
?????

• ??????-??(Peierls-Nabarro)
• ??????????????
• ????????????????
• ????????????????????

32

• ??,d????????,b???????????,?????,?
  ???????
• ??d???,W????,??tP-N??
• ??tP-N?(-d/b)?????,??,d???,b???, tP-N????
• ?????????????????,????????????????????????????????
  ??????????????????

33

• ????????
• ??Cu??????,????(111)??
• ??a-Fe??????,????(110)??
• ??a-Fe??????,????(112)??

34
??????,????????????????????,????????????????????,?
????????,?????????
35
2???

• ???????,??????????????????????????????????????????
  ?

• ??? b. ?? c. ??
• ?????????????????????

36
1)???????

• (111)?fcc????,?(110)???????112,?(110)???????,?(1
  11)????????
• ????--????,??(111)??????????????????

37
????

• ??????????????(???),???????(????)????,?????
  ????,???????????,???????
• ???????????????,????????

38
????

• ???????????????????????????????????(?????????)???
  ????????????????????????????????????????????????
• ????
• FCC111lt112gt
• BCC112lt111gt
• HCP1012lt1011gt -hexagonal close packing

39
????   ???Mg-Li??????????????TEM?
http//blog.sciencenet.cn/blog-114283-504473.html
40
2)?????

1. ???????????????,???????????????????,??????????????
   (??????????),??????????????????????????
2. ?????????????,????????????????,??????????????????
   
3. ???????????????

41

1. ?????????????,????????????????????
2. ?????????,??????
3. ???????????????????,??????????????,?????10?
4. ???????????????????????????????????
5. ???????-????????????????

42
??????????????
43
??-??????????
44
3)?????
?????????????,????????????,?????????????
?????????
45
??????????
Mg-Li?????????????
http//blog.sciencenet.cn/blog-114283-504473.html
46
???????????
R. Zeng et al. / International Journal of Fatigue
32 (2010) 411419
47
? ????,????????(?????)???(????)????????????
48

• ????????????????????,???????,???????????????????
  ?,?????????????????????

???????????
49
4)???????

• ????????????????,???????????????????(???????)?????
  ???????????????????,??
• ?
• ??????????????????ABCABCABC??ABCACBACB(?
  )

50

?????????
51
?????????

• ???
• 1????,???????????????
• 2????,?????????????,??????????????????????????
• 3????????????
• 4??????,?????????

52
?????????

• ???
• 1???????????????,?????????
• 2????????????,??????????????,????????
• 3????????????????,???????????????????,???????????
  ??,????????????????

53

• 4?????????????,??????????
• 5???-??????????,????????,????????
• 6?????????????????????,??????????????????????
• 7???????????????????????????,????????????????????
  

54
3???

• ??????????????,????????????,?????????????????
• ?????,???????,???????????????????,???????

55
????
???????????????

1. ??
2. ??
3. ??

??????????????
56
??????
1???????
2??-??