Dislocation theory

More documents

Recommendations

Info

Stacking faults The wider region between partial dislocation, the lower stacking fault energy • Characteristics of metals with low SPF; 1) Easy to strain harden 2) Easy for twin annealing to occur 3) Temperature dependent flow stress • Aluminium – high stacking fault energy more likely to cross slip. • Copper – lower stacking fault energy cross slip is not prevalent. Partial dislocations Stacking fault Typical values of stacking fault energy Metal Stacking fault energy (mJ m -2 ) Brass 303 stainless steel 304 stainless steel 310 stainless steel Silver Gold Copper Nickel Aluminium Slip plane Model of a stacking fault. Suranaree University of Technology May-Aug 2007 Tapany Udomphol
Frank partial dislocations Frank partial dislocations are another type of partial dislocation in FCC lattice, which provide obstacles to the movement of other dislocations. Frank partial dislocation or sessile dislocation. • A set of (111) plane (viewed from the edge) has a missing middle A plane with a Burgers vector (a o /3) [111] perpendicular to the central stacking fault. • Unlike perfect dislocation, Frank partial dislocation cannot move by glide (sessile dislocation) but by diffusion of atom. Suranaree University of Technology May-Aug 2007 Tapany Udomphol
Page 1 and 2: Dislocation theory Subjects of inte
Page 3 and 4: Objectives • This chapter emphasi
Page 5 and 6: Observation of dislocations A varie
Page 7 and 8: Transmission electron microscope (T
Page 9 and 10: Burgers vector and the dislocation
Page 11 and 12: Burgers circuit Burgers circuit is
Page 13 and 14: Dislocation dissociation Dislocatio
Page 15: Dissociation of a dislocation into
Page 19 and 20: Dislocations in HCP lattice • Sli
Page 21 and 22: Stress fields of dislocations A dis
Page 23 and 24: Forces on dislocation ds b dl Force
Page 25 and 26: Dislocation climb Dislocation climb
Page 27 and 28: Jogs and Kinks Jogs are steps on th
Page 29 and 30: Intersection of two dislocations 2)
Page 31 and 32: Jogs • A stable jog length of the
Page 33 and 34: Dislocation Sources • All metals
Page 35 and 36: Dislocation-point Dislocation point
Page 37: References • Dieter, G.E., Mechan

Dislocation theory

Create successful ePaper yourself

Delete template?

Save as template?