The interaction of parallel edge dislocations with a simple tilt dislocation wall—II. Nonparallel Burgers vectors

keine

einphasige

Entmischung

besteht kein Zusammenhang einer einphasigen

bewirken,

Entmischung

flus&

Ob die durch

mente auftretenden geschwindigkeit

die

iibereinstimmt.

den Zusatz mit

dieser Ele-

Furthermore,

the force exerted

writerc

der

Leerstellen

of the approaching dislocation,

dislocation.

while the force exerted

to the slip plane or the climb

climb behavior

of the approaching

force,

can affect

of the approaching

dislocation.

and compared

who are interested Fundamental

Plaustlud

in creep.

with that of those The results are

1. W. KI)sTE~ untl IV. KNORR, Z. Metullk. 45, 616 (1954). 2. H. S. ROEENBAUIX und D. TURNBULL, Acta Met. 6, 653 (1958). 3. H. S. ROSENB~ZIW und 11. TURNBULL, Acta Met. 7, 664 I1 \--.9591. 4. G. THOMAS, J. Inst. Met. 90, 57 (1961/62). 5. K. KBSTLIN und 0. SCHAABER, Hiirtereitechnik u. WiirmebehantUg.5, 211 (1959). 6. D. TV. EVANS, AZuminium 38, 219 (1962). 5. W. A. ANDERSON in Precipitation from Solid Solution, S. 15.5 Amer. Sot. Metals, Cleveland (1959). 8. A. SAULNIER, Mem. Ski. Rev. Met. 58, 615 (1961). !). C. PANSERI. F. GATTO llnd T. FEDERIGHI, Acta Met. 6, 198 (1958). I

description

Research

Laboratory

PR-118,

between

two parallel edge disby a slip force and a

climb force exerted by one dislocation function of relative orientation edge dislocations.

on the other as a

and position of the two

The contours for the slip force and

for the climb force for several relative orientations the

is a

and results.

is shown graphically

Burgers

dependence

vectors

are

compared.

The

of each force is analyzed

for extremum

forces

of

angular

and the angles

arc‘ evaluated.

action of one dislocation

13, 1962.

Report

The following

of all the calculations

1. The interaction locations

those

can write to ask for U.S. Steel

of bhe same title as this Letter.

Literatur

I\‘ovemhrr

The

too bulky to be published in Acta Metallurgica;

B~HM

the

in cold deforma-

tlxerted by a single edge dislocation.

der RerqakadwniP

only

In the present report. the nature of both these forces has been studied

Vntersuchungen

by

disloca-

tion, or the slip force, can affect only the slip behaviour

tion while the climb force is more important

Einfluss

der

disloca-

the wall in the slip plane of the approaching

dem

Mrtallkumlr

* Rccciwd

be investigated.

slip force is therefore more important

H. fiir

can help or resist the approaching

tion to go through the wall and therefore also should

der Ausscheidungs-

geklhrt wcrdc. /nstitut

dislocation

perpendicular

die Abhgngigkeit

Beweglichkeit

muss durch

beein-

von den Abschreck-

linderungen

ebenfalls

auf

Elementc

Richtung

verstgrkt

der Ausscheidungsgeschwindigkeit bedingungen.

des Siliziums. Ausscheidungs-

in entgegengesetzter

d.h. ein Ca-Zusatz

es

und der Beeinflussung

der Ausscheidungsgeschwindigkeit Durch lialzium dagegen wird die geschwindigkeit

d.h.

zwischen dem Auftreten

The

trapping

on the other is discussed in

detail. 2. The slip force exerted

The interaction of parallel edge dislocations with a simple tilt dislocation wall-II. Nonparallel Burgers vectors* In a previous communication,“) parallel edge dislocation wall was studied.

the interaction

the wall.

vector

dislocation

of a

was limited

dislocation

The study of the interaction

to

has the

as that of the dislocations

on an edge dislocation

parallel edge dislocation

in

was limited to

for several relative orientations

Burgers vectors.

The extremum

graphically

as functions

minimum

distance

Similarly,

of relative orientation

between

the

cluded that the effect of relative

to the slip plane, cannot in this special

case help or resist the approaching through

the

wall.

Although

reveals many interesting dislocation interaction

this

properties

it seems necessary

forces are also shown graphically.

extremum

stress is more

It is con-

orientation

sensit’ive

on the

for gliding

dis-

to go

locations than for climbing dislocations.

previous

study

ing effect of one slip system on the other is thus more

of the simple tilt

to study

the general

important than

when dislocation

when

dislocation

controls

deformation.

Overshooting should thus decrease with the increasing possibility of dislocation climb or with increasing

location and a simple tilt dislocation

perpendicular

graphically

of the approaching

The harden-

slip controls deformation

climb

case in which the approaching edge dislocation has a different Burgers vector from that of the dislocations in the wall. For this general case, the force which is to the slip plane

is calcu-

The extremum

dislocation

wall, in order to understand more fully the between such a wall and parallel edge

dislocations

and of

dislocations.

past another edge dislocation

lated and plotted in the same fashion. climb

perpendicular

two

the climb force exerted on an edge disloca-

tion climbing

the force exerted by the wall in the slip plane of the since the other force, which is

of the two

slip forces are shown

approaching

dislocation

is cal-

culated and plotted versus the position of the gliding

with a simple tilt dislocation

The investigation

the case in which the approaching same Burgers

gliding past another

temperature. 3.

The

interaction

between

a parallel

edge

dis-

wall is also shown

by a slip force and a climb force exerted on

LETTERS

the approaching tation

of

dislocation

the

dislocation Burgers

vector

the

ing dislocation.

dislocation

approaching

of these results have been reported previously.(2) 6. In the appendix

climbing

dislocations.

of the report

the total

Some force

The trapping action of the dislocation

of different Burgers vectors is shown to obey Newton’s

edge dislocation

t,he wall without

is discussed

graphically,

with

largest

J. C. M. Lr Edgur P. Bain Laboratory fat

by the wall on an edge the

third law of motion.

that can

gliding through the wall is calculated

negative forces summarized

in

being trapped.

4. The slip force exerted dislocation

in the

in resisting

exerted on each other by two parallel edge dislocations

There is only one kind of dislocation

penetrate

187

EDITOR

of the position of the approach-

wall on a parallel

shown

of

THE

of the orien-

relative to that of the dislocations

wall and as a function

detail.

as a function

TO

and

Fundamental

Research

United Rtates Steel Corporatiotl

positive

and

Research Center

in a separate graph.

The

Monroaville

Pennsylvania

climb force exerted by the wall on an edge dislocation climbing

are the largest positive and

negative forces exerted on the approaching by the nearest single dislocation concluded

References

through the wall is shown in the same way.

Also shown for comparison

dislocation

in the wall.

It is

that the wall is not much stronger than the

nearest single dislocation

in resisting gliding disloca-

tions and is in general weaker than the nearest’ single

1. J. C. AM.LI, Actn Met. 8, 296 (1960). 2. J. C. M. LI, TheoryofStrengthening by Dislocutim Groupings chapter 15 in Electron Microscopy and Strength of Crysto1.o. edited by G. THOMAS and J. ifTASHBUREi, Int,erscience, t,o be published. * Werrivcd

December

7, 1962.