Study of defects in potassium-doped tungsten alloy by positron annihilation technique

Pei-Yuan Zhang; Ai-Hong Deng; Xue-Fen Tian; Jun Tang

doi:10.7498/aps.69.20191792

Journals >Acta Physica Sinica >Volume 69 >Issue 9 >Page 096103-1 > Article

Acta Physica Sinica
Vol. 69, Issue 9, 096103-1 (2020)

Study of defects in potassium-doped tungsten alloy by positron annihilation technique

Pei-Yuan Zhang¹, Ai-Hong Deng^1,*, Xue-Fen Tian¹, and Jun Tang²

Author Affiliations

¹College of Physics, Sichuan University, Chengdu 610064, China

²Institute of Nuclear Science and Technology, Sichuan University, Chengdu 610064, China

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DOI: 10.7498/aps.69.20191792 Cite this Article

Pei-Yuan Zhang, Ai-Hong Deng, Xue-Fen Tian, Jun Tang. Study of defects in potassium-doped tungsten alloy by positron annihilation technique[J]. Acta Physica Sinica, 2020, 69(9): 096103-1 Copy Citation Text

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Fig. 1. Positron lifetime of vacancies and potassium-containing vacancies in tungsten lattice.

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Distribution of positron annihilation region: (a) 9 × 9 × 9 BCC tungsten lattice supercell with a vacancy; (b) W-GB-1 supercell; (c) W-GB-1 supercell with a vacancy at the GBs; (d) W-GB-1 supercell with a potassium at the GBs.

Fig. 2. Distribution of positron annihilation region: (a) 9 × 9 × 9 BCC tungsten lattice supercell with a vacancy; (b) W-GB-1 supercell; (c) W-GB-1 supercell with a vacancy at the GBs; (d) W-GB-1 supercell with a potassium at the GBs.

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Fig. 3. S-E distribution and fitting curves of PMW and W-K samples with different potassium content.

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Fig. 4. S-W distribution of PMW and W-K samples with different potassium content.

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编号	Σ	GB plane	GB type	Rotation axis	Angle/(°)
W-GB-1	5	$ \langle 210 \rangle $	twist	z(001)	53.15
W-GB-2	13	$ \langle 510 \rangle $	twist	z(001)	22.61
W-GB-3	5	$ \{0\bar1 5\} $	tilt	x(100)	22.61
W-GB-4	13	$ \{0\bar15\} $	tilt	x(100)	53.15

编号	Slip plane(z)	Burgers vector[b]	Dislocation line[y]	Dislocation type	b-y Angle/(°)
W-DL-1	$ (\bar101) $	(111)/2	$ (\bar 12\bar 1) $	EDGE	90
W-DL-2	$ (\bar101) $	(111)/2	(111)	SCREW	0
W-DL-3	$ (\bar101) $	(111)/2	(010)	MIX	54.73

Table 1.

Grain boundary (GB) and dislocation line (DL) model for positron annihilation lifetime calculation

正电子湮没寿命计算中建立的晶界和位错模型

编号	Intact/ps	Vac.1/ps	Vac.9/ps	K1/ps	K9/ps
W-GB-1	116.6	198.2	297.4	110.6	108.4
W-GB-2	117.9	198.0	297.2	116.4	111.7
W-GB-3	135.2	204.8	304.4	142.3	144.1
W-GB-4	142.2	198.0	317.3	141.0	144.6
W-DL-1	133.9	160.3	309.7	133.9	134.2
W-DL-2	106.5	194.7	324.0	104.7	105.8
W-DL-3	123.4	158.0	315.4	123.4	123.4

Table 2.

Positron annihilation lifetime of grain boundary and dislocation with vacancies or potassium atoms.

晶界和位错包含空位或钾原子时的正电子湮没寿命值

钾含量/ppm	编号	${\tau _{{\rm{1, }}\exp }}$/ps	${I_{1, \exp }}$/%	${\tau _{{\rm{2, }}\exp }}$/ps	${I_{2, \exp }}$/%	平均寿命 ${\tau _{{\rm{av}}}}$/ps	捕获率 $\kappa $/ns^–1	计算体寿命 $\tau _{\rm{1}}^{{\rm{cal}}}$/ps
46	A1	123.4	74.62	296.2	25.38	167.3	1.1999	97.2
82	B1	123.3	75.68	305.1	24.32	167.5	1.1752	97.4
122	C1	140.1	72.42	332.6	27.58	193.2	1.1395	97.7
144	D1	143.2	77.07	328.3	22.93	185.6	0.9028	100.1

Table 3.

Two-component positron lifetime of W-K samples with different potassium content.

不同钾含量的钨钾合金样品的双组分正电子寿命值

钾含量/ppm	编号	位错捕获率 ${\kappa _1}$/ps^–1	空位团簇捕获率 ${\kappa _2}$/ps^–1	位错密度 ${C_{{\rm{dis}}}}$/10¹⁰cm²	空位团簇浓度 ${C_{{\rm{cl}}}}$/10^–7
46	A1	0.00912	0.00505	0.8289	1.515
82	B1	0.00895	0.00474	0.8136	1.424
122	C1	0.03359	0.01511	3.0534	4.538
144	D1	0.04400	0.01489	3.9991	4.470

Table 4.

Dislocation and vacancy clusters in W-K samples with potassium content.

不同钾含量的钨钾合金样品中位错和空位团簇

钾含量/ppm	编号	第一层厚度/nm	第一层S₁	第二层S₂
46	A2	10	0.4521	0.4424
82	B2	11	0.4520	0.4406
122	C2	13	0.4521	0.4455
0	PMW	10	0.4050	0.3880

Table 5.

Fitted values of S parameters of W-K samples with different potassium content.

不同钾含量的钨合金样品的S参数拟合

钾含量/ppm	编号	寿命谱 $L_{{\rm{ +, eff}}}^{{\rm{cal}}}$/nm	编号	第一层 $L_{ +, {\rm{eff}}}^1$/nm	第二层 $L_{ +, {\rm{eff}}}^2$/nm
46	A1	77.59	A2	2.73 ± 0.89	59.75 ± 9.96
82	B1	78.39	B2	4.98 ± 1.06	58.61 ± 7.86
122	C1	49.22	C2	1.65 ± 1.56	37.44 ± 7.72
0			PMW	6.50 ± 0.29	109.32 ± 5.46

Table 6.

Positron diffusion length in tungsten alloy samples with different potassium content.

不同钾含量的钨合金样品中正电子扩散长度

Pei-Yuan Zhang, Ai-Hong Deng, Xue-Fen Tian, Jun Tang. Study of defects in potassium-doped tungsten alloy by positron annihilation technique[J]. Acta Physica Sinica, 2020, 69(9): 096103-1

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