W.N.Liu 1)
,
M.N.Fang 2)
,
J.Xing 1) and Y.W.Liu 3) 1) Department of Mechanical Engineering
,
Changchun Institute of Optics and Fine Mechanics
,
Changchun 130022
,
China 2) Changchun Institute of Post and Telecommunications
,
Changchun 130022
,
China 3) Changchun Institute of Optics and Fine Mechanics
,
Changchun 130022
,
China
金属学报(英文版)
In this paper, we describe the laser heat-treating experiment results of three kind tool high-speed steel test samples. After laser quenching and tempering of three kinds of annealed tool high speed steel (W18Cr4V, W9Mo3Cr4V1, W6Mo5Cr4V2) test samples, we used microhardness-measure to test the samples and analyzed such problems as the hardness and depth of hardening quenching layer. Furthermore, after laser quenching and tempering of the quenched and three time tempered high speed steel (W18Cr4V) and its hardness analyzing, we got lase quenching's different results of the samples under different initial heat treating.
关键词:
high-speed steel
,
null
,
null
B.W. Wang
,
H. Shen
金属学报(英文版)
Ni-Cr System solar selective thin solid films were prepared by d.c. magnetron reactivesputtering under the atmosphere of O2 and N2. Ni-Cr alloy was chosen as targetmaterial and copper sheets as substrate. Using SEM, Spectrophotometer and Talystepto analyze the relations between the selective characteristic and the structure, theformation and the thickness of the thin films. The aim is to obtain good solar selectivethin films with high absorptance and low emittance, which is applied to flat plate solarheat collectors.
关键词:
solar selective thin film
,
null
,
null
,
null
Lixing HUO
,
Furong CHEN
,
Yufeng ZHANG
,
Li ZHANG
,
Fangjun LIU
,
Gang CHEN
材料科学技术（英文）
The electron beam local post-weld heat treatment (EBLPWHT) is a rather new method that provides the advantages of high precision, flexibility and efficiency, energy saving and higher productivity. This paper studies the effect of two post-weld heat treatment processes on the microstructure, mechanical properties and fracture toughness of an electron beam welded joints in 30CrMnSiNi2A steel. EBLPWHT, in a vacuum chamber, immediately after welding and a traditional furnace whole post-weld heat treatment (FWPWHT) were compared. The experimental results show that, after EBLPWHT treatment, the main microstructure of weld was changed from coarse acicular martensite into lath martensite, HAZ was changed from lath martensite, bainite into lower bainite, and base metal was changed from ferrite and pearlite into upper bainite and residual austenite. The microstructures of different zones of joints in FWPWHT condition were tempered sorbite. The properties of welded joints can be improved by the EBLPWHT in some extent, and especially largely for the fracture toughness of welded joints. However the value of fracture toughness of base metal is comparatively low, so appropriate heat treatment parameters should be explored in the future.
关键词:
Post-weld heat treatment
,
null
,
null
,
null
SUN Wenqiang
,
CAI Jiuju
,
MAO Hujun
,
GUAN Duojiao
钢铁研究学报(英文版)
As the largest energy consuming manufacturing sector and one of the most important sources of carbon dioxide (CO2) emissions, the China′s iron and steel industry has paid attention to the study of changing trend and influencing factors of CO2 emissions from energy use. The logarithmic mean Divisia index (LMDI) technique is used to decompose total change in CO2 emissions into four factors: emission factor effect, energy structure effect, energy consumption effect, and steel production effect. The results show that the steel production effect is the major factor which is responsible for the rise in CO2 emissions; whereas the energy consumption effect contributes most to the reduction in CO2 emissions. And the emission factor effect makes a weak negative contribution to the increase of CO2 emissions. To find out the detailed relationship between change in energy consumption or steel production and change in CO2 emissions, the correlation equations are also proposed.
关键词:
CO2 emissions
,
energy use
,
LMDI technique
,
steel production
,
energy consumption
American Mineralogist
A natural high-pressure phase of titanium oxide with alpha-PbO2-structure has been found in omphacite from coesite-bearing eclogite at Shima in the Dabie Mountains, China. High-resolution transmission electron microscope observations have revealed an orthorhombic lattice, corresponding to alpha-PbO2-type TiO2, with cell parameters a = 0.461 nm, b = 0.540 nm, c = 0.497 nm and space group Pbcn. It occurs as nanometer-thick (< 2 nm) lamellae between multiple twinned rutile crystals, providing additional evidence of very high-pressure, metamorphism at 7 GPa, 900 degrees C. This implies subduction of continental material to a depth of more than 200 kilometers. alpha-PbO-type TiO2 could be an extremely useful index mineral for ultrahigh-pressure.
关键词:
high-pressure phase;ries crater;rutile;polymorph;titanium
材料科学技术（英文）
The relationship of "preparation parameters-microstructures-wettability" of TiO2 films was reported. In this work, TiO2 films were deposited onto glass and silicon substrates by using mid-frequency dual magnetron sputtering technique at ambient temperature with various power densities and deposition time. After deposition, the films were heat treated at different annealing temperatures. X-ray diffraction (XRD), Raman spectroscopy, and field-emission scanning electron microscopy (FE-SEM) were utilized to characterize TiO2 films. The wettability of the films was evaluated by water contact angle measurement. The phase transition temperature of TiO2 films depended on the power density. It was demonstrated that wettability was strongly structure dependent and the film with the thickness of 610 nm (the power density was 2.22 W/cm(2)) showed the lowest contact angle (8). It can be concluded that smaller crystallite size, the rutile phase with (110) face being parallel to the surface, and tensile stress favored the hydrophilicity of the TiO2 films.
关键词:
titanium dioxide;reactive magnetron sputtering;phase composition;microstructure;hydrophilicity;thin-films;titanium-dioxide;photoinduced hydrophilicity;surfaces;anatase;conversion;photocatalysis;enhancement;electrode;stress
Surface & Coatings Technology
Ti-Al-N films with different compositions were prepared by varying the nitrogen flow rate using pulsed magnetron sputtering and subsequently annealed in air at 700 degrees C. The microstructure and microhardness of the films were investigated before and after heat treatment. The XRD results indicate that no Ti2AlN MAX phase occurs in all the as-deposited films. Ti2AlN phases could be acquired only after annealing via solid state reaction. The formation condition of Ti2AlN phase is strongly dependent on the film composition. It has been found that the nitrogen concentration in the films plays a key role for the phase formation, and the critical value is in the range of 22.5-29.6 at.%. The fractured cross-section SEM images show that all the as-deposited films exhibit a fine columnar morphology. The annealed films with Ti2AlN phase components change the morphology from columnar to fine equiaxed polycrystalline. In addition, the microhardness of the films containing Ti2AlN phase is also explored, which is within the range of 18-24 GPa. (C) 2011 Elsevier B.V. All rights reserved.
关键词:
Magnetron sputtering;Heat treatment;Microstructure;Ti2AlN phase;Ti-Al-N films;thin-films;m(n+1)ax(n) phases;corrosion;ti3sic2;growth;cr2alc
MA Zongyi YAO Zhongkai Harbin Institute of Technology
,
Harbin
,
China
金属学报(英文版)
The SiC_w/Al composite prepared by squeeze casting has a combination of superior room temperature specific strength and modulus together with excellent thermal properties.The extrusion can make an improvement on the strength and ductility of the composite from 582 MPa as squeeze casted up to 639 MPa,and on the transformation from isotropic to the anisotropic structure.This seems to be explained by the orientation of whiskers and the densification of dislocations in matrix.TEM observation indicates that the stacking fault is the usual planar defect on the SiC_w surface. composite;;SiC whisker;;Al alloy;;microstructure
关键词:
composite
,
null
,
null
,
null
Insup Lee
,
Kwang-Ho Jeong
材料科学技术（英文）
Plasma nitrocarburizing and plasma oxidizing treatments were performed to improve the wear and corrosion resistance of SKD 61 steel. Plasma nitrocarburizing was conducted for 12 h at 540℃ in the nitrogen, hydrogen and methane atmosphere to produce the ε-Fe2–3 (N,C) phase. The compound layer produced by plasma nitrocarburising was predominantly composed of ε-phase, with a small proportion of γ′-Fe4(N,C) phase. The thickness of the compound layer and the diffusion layer are about 10 μm and about 200 μm, respectively. Plasma post oxidation was performed on the nitrocarburized samples with various oxygen/hydrogen ratio at constant temperature of 500℃ for 1 h. The very thin magnetite (Fe3O4) layer of 1–2 μm in thickness on top of the compound layer was obtained. Anodic polarization test revealed that plasma nitrocarburizing process contributed a significant improvement of corrosion resistance of SKD 61 steel. However, the corrosion characteristics of the nitrocarburized compound layer was deteriorated by oxidation treatment.
关键词:
Plasma nitrocarburizing
,
null
,
null
,
null
,
null
,
null
,
null
Physica B-Condensed Matter
We have studied the effects of Si ion implantation and post-annealing on yellow luminescence (YL) from GaN. Two types of GaN samples grown by the metal-organic chemical vapor deposition method and labeled as GaN1 and GaN2 were studied. The PL spectrum of the as-grown GaN1 sample was dominated by a strong YL and that of the as-grown GaN2 sample was almost free from YL. After Si ion implantation with doses of both 1.3 x 10(13) and 1.0 x 10(16)cm(-2), the intensity ratios of YL to near band edge (NBE) emission (I-Y/I-NBE) for the GaN1 samples decreased markedly compared with those of the corresponding unimplanted ones both before and after post-annealing at temperatures up to 950degreesC. However, for the Si-ion-implanted GaN2 sample with a dose of 1.3 x 10(13)cm(-2), I-Y/I-NBE increased compared with that of the as-grown one both before and after post-annealing. Besides, the I-Y/I-NBE for Si-ion-implanted GaN1 with a dose of 1.3 x 10(13) cm(-2) increased monotonically with annealing temperature. Our results show that only the Si ion implantation being accompanied with high-temperature post-annealing could produce YL. The possible reasons for the marked reduction in I-Y/I-NBE for the GaN1 sample after Si-ion-implantation have been discussed. (C) 2002 Elsevier Science B.V. All rights reserved.
关键词:
photoluminescence;yellow luminescence;ion implantation;GaN;detected magnetic-resonance;vapor-phase epitaxy;laser-diodes;undoped;gan;photoluminescence;vacancies;layers;origin
