钽合金表面渗碳层中碳化物析出及其性能的第一性原理研究

钽合金表面渗碳层中碳化物析出及其性能的第一性原理研究

孟祥龙, 刘瑞良, Li D. Y.

First Principles Study on the Precipitation and Properties of Carbides in the Surface Carburized Layer of Tantalum Alloys

MENG Xianglong, LIU Ruiliang, Li D. Y.

表2 含W复合碳化钽结构的晶体参数、E_f和E_c

Table 2 Lattice parameters, E_f, and E_c of complex tantalum carbide with W

Crystal structure	Carbide	Lattice constant nm	Angle (°)	Volume nm³	E_f eV·atom^-1	E_c eV·atom^-1
fcc	TaC, this work	$\bar{a}$ =0.44781	α = β = γ = 90.00	0.71839	-0.5962	-8.5998
	TaC^[34]	a = 0.447			-0.59
	Ta_0.75W_0.25C	$\bar{a}$ = 0.44543	α = 90.00, β = 89.99, γ = 90.00	0.70699	-0.3759	-8.6364


	Ta_0.5W_0.5C	$\bar{a}$ = 0.44339	α = 89.79, β = 90.19, γ = 90.06	0.69731	-0.1566	-8.2123


	Ta_0.25W_0.75C	$\bar{a}$ = 0.44096	α = β = 90.00, γ = 90.06	0.68590	0.0565	-8.3138
			α = β = 90.00, γ = 90.06
	WC	$\bar{a}$ = 0.43821	α = β = γ = 90.00	0.67320	0.2909	-7.8169
hcp	Ta₂C	a = b = 0.31249, c = 0.49593	α = β = 90.00, γ = 120.00	0.33551	-0.6163	-8.6566
	(P $\bar{3}$ m1, this work)	a = b = 0.31249, c = 0.49593	α = β = 90.00, γ = 120.00
	Ta₂C (P $\bar{3}$ m1)^[34]	a = b = 0.311, c = 0.495	γ = 120		-0.60
		a = b = 0.311, c = 0.495
	Ta_0.75W_0.25C	a = 0.45263, b = 0.45262, c = 0.43127	α = 89.94, β =90.08, γ = 120.00	0.61212	-0.1640	-8.1946


	Ta_0.5W_0.5C	a = 0.44731, b = 0.44718, c = 0.43034	α = 89.93, β = 89.98, γ = 120.00	0.59638	-0.1561	-8.2137


	Ta_0.25W_0.75C	a = 0.44306, b = 0.44305, c = 0.42889	α = 90.00, β = 89.99, γ = 119.99	0.58335	-0.1573	-8.2381


	WC	a = b =0.43868, c = 0.42730	α = β = 90.00, γ = 120.00	0.56968	-0.1543	-8.2621
		a = b =0.43868, c = 0.42730	α = β = 90.00, γ = 120.00