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1 含Mo复合碳化钽结构的晶体参数、形成能(E_f)和内聚能(E_c)

Table 1 Crystallographic parameters, formation energy (E_f), and cohesive energy (E_c) of complex tantalum carbide with Mo

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_0.75Mo_0.25C	$\bar{a}$ = 0.44554	α = 90.04, β = γ = 90.00	0.70753	-0.4089	-8.1705
	Ta_0.5Mo_0.5C	$\bar{a}$ = 0.44320	α = β =89.78, γ = 90.22	0.69645	-0.2246	-7.7442
	Ta_0.25Mo_0.75C	$\bar{a}$ = 0.44061	α = 89.79, β = γ = 90.00	0.68428	-0.0432	-7.6155
	MoC	$\bar{a}$ = 0.43699	α = β = γ = 90.00	0.66756	0.1400	-6.8956
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 = 120.00		-0.60
		a = b = 0.311, c = 0.495	γ = 120.00
	Ta_0.75Mo_0.25C	a = 0.45271, b = 0.45256, c = 0.43049	α = 90.05, β = 89.96, γ = 120.01	0.68590	-0.1681	-7.9208


	Ta_0.5Mo_0.5C	a = 0.44703, b = 0.44702, c = 0.42883	α = 90.07, β = 89.98, γ = 120.01	0.59361	-0.1616	-7.6633


	Ta_0.25Mo_0.75C	a = 0.44261, b = 0.44227, c = 0.42681	α = 89.99, β = 90.01, γ = 120.02	0.57870	-0.1610	-7.4476


	MoC	a = b = 0.43761, c = 0.42422	α = β = 90.00, γ = 120.00	0.56283	-0.1519	-7.1876
		a = b = 0.43761, c = 0.42422	α = β = 90.00, γ = 120.00