Question: Can't define function dependendy

in following coding
final equations Exp1 ,Exp2, Exp3, Exp4 depends on X2 and X3, but in these equations I have introduced certain equations which are also depending on X2 and X3,like fccL[Ni, Si] etc, but that dependend variable is counted as different variable while plotting the function or evaluating it Help me please 

> restart;> NULL;> ;>
R := 8.314;>
G1[1] := piecewise(298 <= T and T < 1358, -7770.458+130.485235*T-24.112392*T*ln(T)-0.265684e-2*T^2+0.129223e-6*T^3+52478/T, `and`(T >= 1358, T < 3200), -13542.026+183.803828*T-31.38*T*ln(T)+0.364167e30/T^9, 0);>
G1[2] := piecewise(298 <= T and T < 1358, 5194.277+120.973331*T-24.112392*T*ln(T)-0.265684e-2*T^2+0.129223e-6*T^3+52478/T-0.58489e-20*T^7, `and`(T >= 1358, T < 3200), -46.545+173.881484*T-31.38*T*ln(T), 0);>
G1[3] := piecewise(298 <= T and T < 1358, -7170.458+130.685235*T-24.112392*T*ln(T)-0.265684e-2*T^2+0.129223e-6*T^3+52478/T, `and`(T >= 1358, T < 3200), -12942.026+184.003828*T-31.38*T*ln(T)+364.167*E27/T^9, 0);>
G1[4] := piecewise(298 <= T and T < 1358, -3753.458+129.230235*T-24.112392*T*ln(T)-0.265684e-2*T^2+0.129223e-6*T^3+52478/T, `and`(T >= 1358, T < 3200), -9525.026+182.548828*T-31.38*T*ln(T)+0.364167e30/T^9, 0);> qTc[2] := 633; qB0[fcc] := .52; qA[2] := 0.6533939e-5; qA0[2] := 0.3103614e-4; qA1[2] := 0.2418404e-7; qK0[2] := 0.53297107e-11; qK1[2] := 0.45132279e-15; qK2[2] := 0.97669517e-18; qn := 4.651; qA2[2] := 0; qA3[2] := 0; P := 1.05*10^5; qD[bcc] := 518/1125+11692/15775*(1/qp[bcc]-1); qp[bcc] := .40; qp[others] := .28; qD[others] := 518/1125+11692/15775*(1/qp[others]-1); qB0[hcp] := .52; qTc[2*bcc] := 575; qB0[2*bcc] := .85;> G[pres] := qA[2]*exp(qA0[2]*T+(1/2)*qA1[2]*T^2+(1/3)*qA2[2]*T^3+qA3[2]/T)*(1+qn*P(qK0[2]+qK1[2]*T+qK2[2]*T^2)^(1-1/qn)-1)/((qK0[2]+qK1[2]*T+qK2[2]*T^2)*(qn-1));> gtau[bcc] := piecewise(T/qTc[2*bcc] <= 1, 1-(79*(T/qTc[2*bcc])^(-1)/(140*qp[bcc])+(474/497*(1/qp[bcc]-1))*((1/6)*(T/qTc[2*bcc])^3+(1/135)*(T/qTc[2*bcc])^9+(1/600)*(T/qTc[2*bcc])^15))/qD[bcc], T/qTc[2*bcc] > 1, -((1/10)*(T/qTc[2*bcc])^(-5)+(1/315)*(T/qTc[2*bcc])^(-15)+(1/1500)*(T/qTc[2*bcc])^(-25))/qD[bcc]);> gtau[others] := piecewise(T/qTc[2] <= 1, 1-(79*(T/qTc[2])^(-1)/(140*qp[others])+(474/497*(1/qp[others]-1))*((1/6)*(T/qTc[2])^3+(1/135)*(T/qTc[2])^9+(1/600)*(T/qTc[2])^15))/qD[others], T/qTc[2] > 1, -((1/10)*(T/qTc[2])^(-5)+(1/315)*(T/qTc[2])^(-15)+(1/1500)*(T/qTc[2])^(-25))/qD[others]);> G[mag(bcc)] := R*T*ln(qB0[2*bcc]+1)*gtau[bcc];> G[mag(fcc)] := R*T*ln(qB0[fcc]+1)*gtau[others];> G[mag(hcp)] := R*T*ln(qB0[hcp]+1)*gtau[others];> G2[1] := piecewise(298 <= T and T < 1728, -5179.159+117.854*T-22.096*T*ln(T)-0.48407e-2*T^2+G[pres]+G[mag(fcc)], `and`(T >= 1728, T < 3000), -27840.620+279.134977*T-43.1*T*ln(T)+0.112754e32/T^9+G[pres]+G[mag(fcc)], 0);> G2[2] := piecewise(298 <= T and T < 1728, 11235.527+108.457*T-22.096*T*ln(T)-0.48407e-2*T^2-0.382318e-20*T^7, `and`(T >= 1728, T < 3000), -9549.817+268.597977*T-43.1*T*ln(T), 0);> G2[3] := piecewise(298 <= T and T < 1728, -4133.159+119.1092*T-22.096*T*ln(T)-0.48407e-2*T^2+G[mag(hcp)], `and`(T >= 1728, T < 3000), -26794.620+280.390177*T-43.1*T*ln(T)+0.112754e32/T^9+G[mag(hcp)], 0);> G2[4] := piecewise(298 <= T and T < 1728, 3535.925+114.298*T-22.096*T*ln(T)-0.48407e-2*T^2+G[mag(bcc)], `and`(T >= 1728, T < 3000), -19125.536+275.578977*T-43.1*T*ln(T)+0.112754e32/T^9+G[mag(bcc)], 0);> G3[1] := piecewise(298 <= T and T < 1687, 42837.391+115.436859*T-22.8317533*T*ln(T)-0.1912904e-2*T^2-0.3552e-8*T^3+176667/T, `and`(T >= 1687, T < 3600), 41542.358+145.481367*T-27.196*T*ln(T)-0.420369e31/T^9, 0);> G3[2] := piecewise(298 <= T and T < 1687, 42533.751+107.13742*T-22.8317533*T*ln(T)-0.1912904e-2*T^2-0.3552e-8*T^3+176667/T+0.209307e-20*T^7, `and`(T >= 1687, T < 3600), 40370.523+137.722298*T-27.196*T*ln(T), 0);> G3[3] := piecewise(298 <= T and T < 1687, 41037.391+116.436859*T-22.8317533*T*ln(T)-0.1912904e-2*T^2-0.3552e-8*T^3+176667/T, `and`(T >= 1687, T < 3600), 39742.358+146.481367*T-27.196*T*ln(T)-0.420369e31/T^9, 0);> G3[4] := piecewise(298 <= T and T < 1687, 38837.391+114.736859*T-22.8317533*T*ln(T)-0.1912904e-2*T^2-0.3552e-8*T^3+176667/T, `and`(T >= 1687, T < 3600), 37542.358+144.781367*T-27.196*T*ln(T)-0.420369e31/T^9, 0);> LiqL[Cu, Ni] := 11760+1.084*T+(-1672)*(X1-X2);> LiqL[Cu, Si] := -38764+12*T+(-52431+27.457*T)*(X1-X3)+(-29427+14.775*T)*(X1-X3)^2;> LiqL[Ni, Si] := -205000+33*T+(-102700+27*T)*(X2-X3)+25000*(X2-X3)^2+(117000-55*T)*(X2-X3)^3;> LiqL[Cu, Ni, Si] := (-428000+100*T)*X1+(-140000+100*T)*X2+(-260000+100*T)*X3;> fccL[Cu, Ni] := 8366+2.802*T+(-4360+1.812*T)(X1-X2);> fccL[Cu, Si] := -42204+13.891*T+(-1102-18.178*T)(X1-X3);> fccL[Ni, Si] := -205000+30*T+(-52000+20*T)*(X2-X3);> fccL[Cu, Ni, Si] := (-350000+100*T)*X1+(-300000+100*T)*X2+(800000+100*T)*X3;> bccL[Cu, Ni] := 8366+2.802*T;> bccL[Cu, Si] := (-26447)+10.216+(-47275-8.517*T)*(X1-X3);> bccL[Ni, Si] := fccL[Ni, Si];> bccL[Cu, Ni, Si] := (-470000+100*T)*X1+0*X2+0*X3;> hcpL[Cu, Ni] := 8366+2.802*T;> hcpL[Cu, Si] := -26799-.732*T+(-28065-0.29e-1*T)*(X1-X3);> hcpL[Ni, Si] := 50000;> hcpL[Cu, Ni, Si] := (-707000+100*T)*X1+0*X2+0*X3;> X1 := 1-X3-X2;>

Exp1 := proc (X2, X3) options operator, arrow; G1[1]*X1+G2[1]*X2+G3[1]*X3+R*T*(X1*ln(X1)+X2*ln(X2)+X3*ln(X3))+X1*X2*fccL[Cu, Ni]+X1*X3*fccL[Cu, Si]+X2*X3*fccL[Ni, Si]+X1*X2*X3*fccL[Cu, Ni, Si] end proc;>

Exp2 := proc (X2, X3) options operator, arrow; G1[2]*X1+G2[2]*X2+G3[2]*X3+R*T*(X1*ln(X1)+X2*ln(X2)+X3*ln(X3))*X1*X2*LiqL[Cu, Ni]+X1*X3*LiqL[Cu, Si]+X2*X3*LiqL[Ni, Si]+X1*X2*X3*LiqL[Cu, Ni, Si] end proc;>

Exp3 := proc (X2, X3) options operator, arrow; G1[3]*X1+G2[3]*X2+G3[3]*X3+R*T*(X1*ln(X1)+X2*ln(X2)+X3*ln(X3))*X1*X2*hcpL[Cu, Ni]+X1*X3*hcpL[Cu, Si]+X2*X3*hcpL[Ni, Si]+X1*X2*X3*hcpL[Cu, Ni, Si] end proc;>

Exp4 := proc (X2, X3) options operator, arrow; G1[4]*X1+G2[4]*X2+G3[4]*X3+R*T*(X1*ln(X1)+X2*ln(X2)+X3*ln(X3))*X1*X2*hcpL[Cu, Ni]+X1*X3*hcpL[Cu, Si]+X2*X3*hcpL[Ni, Si]+X1*X2*X3*hcpL[Cu, Ni, Si] end proc;> with*plots;> Loading plots> animate(plot3d, [[Exp1(X2, X3), Exp2(X2, X3), Exp3(X2, X3), Exp4(X2, X3)], X3 = 0 .. 1, X2 = 0 .. 1], T = 300 .. 1500);> > 
> > Exp4(.5, .2);> > > > >