清华大学：《材料科学基础》课程教学资源（PPT课件讲稿）Chapter 5.16 Dislocation in FCC crystals

85.16 Dis location in FCC crystals I Per fect dis locat ion b=na。+n2b+n2c For FCC b=- Glide plane Burgers tor b o b a b o

§5.16 Dislocation in FCC crystals ◆ Ⅰ.Perfect dislocation        b n a n b n c = 1 + 2 + 2 = 110  2 1 For FCC b 

[10]→>=[211]+-[121

[121] 6 1 [211] 6 1 [110] 2 1 → +

II. Shock ley partial dislocation B C A b=-[101 The slip movement of a perfect dislocation consists of two steps, This can be expressed in terms of vector combination:11011=121+(2111

◆ Ⅱ.Shockley partial dislocation C A B [101] 2 1 b =  The slip movement of a perfect dislocation consists of two steps, This can be expressed in terms of vector combination: [211] 6 1 [112] 6 1 [101] 2 1 = +

The Shockley partial is the line of demarcation on slip plane [111 between slipped and unslipped zones, the slip vector being It also the boundary line between faulted and unfaulted zones

The Shockley partial is the line of demarcation on slip plane {111} between slipped and unslipped zones, the slip vector being . It also the boundary line between faulted and unfaulted zones. 112  6 1

[110 001 未滑001 已滑 - 4。404-c B B→C 112 FCC{111 BCC{112}

FCC {111} BCC {112} HCP {1012}1011 A C B A C A C B A C B A C [110] [001] [110] [112] 2 1 [001] 未滑 已滑

Characteristic of Shockley Partial 1. It is the boundary between faulted and unfaulted 2. It can be edge, screw or mixed zones dislocation 3. Even in edge orientation, it can not climb Even in screw orientation, it can not cross slip 4. It can move only on faulted plane(slip) shockley partial

Characteristic of Shockley Partial: 1. It is the boundary between faulted and unfaulted. 2. It can be edge, screw or mixed zones dislocation. 3. Even in edge orientation, it can not climb. Even in screw orientation, it can not cross slip. 4. It can move only on faulted plane (slip) shockley partial

◆Ⅲ. Extended dis| ocation b:[110 b1:[211 [121]

◆ Ⅲ.Extended dislocation A A A A A C B A B B b b1 b2 [1 21] 6 1 : [211] 6 1 : [1 10] 2 1 : 2 1 b b b

unslipped ppe unfaulted (faulted) zones b 2 2] [211 Two parallel shockley partial dislocations separated by a faulted zone constitute an extended dislocation

unslipped unfaulted slipped (faulted) zones [121] 6 1 [211] 6 1 I II III 1 b 2 b Two parallel shockley partial dislocations separated by a faulted zone constitute an extended dislocation

BABB CICC以C ⅩBXBB BXBYBYB BIBEB BaB CXCAC BXBYBXB CKCACXC BXBAB (BIBAB BXBXBXBXB CXCⅩCXC BBO B CIC 68O

85.17 Frank Partial Dislocation in FCC 1. Frank Partial is formed by extracting or inserting part of (111 plane ACBACBACBA ACBA BACBA ACBACBACB BACBACBA BACBCACBA BACBACBA negative Frank positive Frank b=1 b=1<11l intrinsic stacking fault extrinsic stacking fault

§5.17 Frank Partial Dislocation in FCC 1. Frank Partial is formed by extracting or inserting part of {111} plane. negative Frank positive Frank = 111 3 1 b  intrinsic stacking fault = 111 3 1 b  extrinsic stacking fault