Investigation on Dynamic Recrystallization Behavior of Martensitic Stainless Steel

Algorithm 1

%=====================================================================

% Calculation of adjustable constants of (1)(psi and zeta)

% Fei CHEN

% 25.12.2013

%=====================================================================

%The needed information is the stress-strain curve data

%These points should be provided in a variable named

%“DATA_T_STRAINRATE”

%The variable “DATA_T_STRAINRATE” should be in format of (strain,

%stress) in 2 columns

%=====================================================================

clc;

clear all;

a=load(‘DATA_T_STRAINRATE’);% reading the experimental data

N=size(a); N=N(1);%Number of rows

s0=a(1,2);%Value of initial stress

sp=max(a);sp=sp(2);%Value of peak stress

Q=size(a); Q=Q(1);%Number of rows

for i=1:Q;

 if(a(i,2)==sp)

 ep=a(i,1);% Value of peak strain

 M=i;

 end

end

for i=1:M

 b(i,1)=a(i,1);

 b(i,2)=a(i,2);

end

x1=b(:,1);

y1=b(:,2);

for i=1:M

 c(i,1)=a(i,1)/ep;

 c(i,2)=a(i,2)/sp;

end

x2=c(:,1);

y2=c(:,2);

k0=[0.001,0.001];

x=0:0.001:1;

f1=@(k,x) (1-exp(k(1)*(x). ^∧k(2)));

for i=1:1000

k=lsqcurvefit(f1,k0,x2,y2);%the method of least squares

k0=k;

end

y=1-exp(k(1)*(x). ^∧k(2));

for i=1:M

 d(i,1)=b(i,1);

 d(i,2)=sp*(1-exp(k(1)*c(i,1). ^∧k(2)));

end

%psi=k(1)

%zeta=k(2)

%=====================================================================

%Following lines could be used to compare the predicted data with the

%experimental data

%=====================================================================

%x3=d(:,1);

%y3=d(:,2);

%subplot(1,2,1),plot(x2,y2,‘b:*’)

%hold on

%subplot(1,2,1),plot(x,y,‘g:+’);

%hold off

%subplot(1,2,2),plot(x1,y1,‘b:*’)

%hold on

%subplot(1,2,2),plot(x3,y3,‘g:+’)

%hold off