C.Z. Chen1
,
2)
,
T.Q. Lei2)
,
D.W. Cui1)and J.H. Yu1) 1) College of MaterialScience and Technology
,
Shandong University of Technology
,
Jinan 250061
,
China2) College of MaterialScience and Technology
,
Harbin Institute of Technology
,
Harbin 150001
,
China
金属学报(英文版)
The microstructure and formation mechanism of laser clad Ni60 Acoating were studied by meansof XRD, SEM, TEMand EDAXetc. Theresultsshow thatthe microstructureofthe coatingiscontrolled bytheratiooftemperature gradient Gand solidification speed υ( G/υ)atthesolid liquidinterface. Attheinterfaceof molten pool/substrate, G/υisquitelarge,and Ni basedsolid solutionsgrowingintheform oflow speed planar grain boundary form abonding belt. With the advancement of the solid liquid interface, G/υdecreases, and a bonding zone mainly composed ofcomplex cellulareutecticsof Ni+ M23( CB)6 and Ni+ Ni3Bisformed when G/υisstilllargeenough. Further decrease willlead to a clad layerthat exhibitscellular and dendritic Ni basedsolidsolutions,dendriticor discontinuousnetwork M7( CB)3 and complex eutectics( Ni+ M23( CB)6 and Ni+ Ni3 B) between them .
关键词:
microstructure
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null
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null
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null
Q. Y. Liu1
,
2) W. D. Fei2) and N. G. Liang1) 1) LNM
,
Institute of Mechanics
,
The Chinese Academy of Sciences
,
Beijing 100080
,
China 2) Schoolof Materials Science and Engineering
,
Harbin Institute of Technology
,
Harbin 150001
,
China
金属学报(英文版)
heinteracteach other among three kindsofthermalresidualstresses were analyzed firstly. Theresultsshown thatthe presenceof microstressandthermal mismatch stresshad noinflu enceon the measurement of macrostress, but macrostress can affect the measured value of thermal mismatch stress. Theeffectofthicknessofspecimen on thermalresidualstresses was discussed. Macrostresscan be neglected in thin specimen, thermal mismatch stressincreased with quenchingtemperatureincreasing, andobtainedtheir maximum valuesat400 ℃,then decreased . Forthethickspecimen, thecompressive macrostressatthesurfaceincreased with the quenching temperature increasing. The changing tendency of thermal mismatch stresswith quenchingtemperature wasquite differentcompared withthethinspecimens, which ob tainedtheir minimum valueat400℃.
关键词:
thermalresidualstresses
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null
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null
G.Li
,
L.F.Xia
,
X.X.Ma
,
Y.Sun and Z.J.Zhan Schoolof Materials Science and Engineering
,
Harbin Institute of Technology
,
Harbin 150001
,
China
金属学报(英文版)
The bondstructureofhydrogenated diamond likecarbon( DLC) filmsdeposited with plasmabased ionimplantation ( PBII) wascharacterized by Raman spectroscopy andcore level band and valenceband spectrum of XPS. Theresultsshow thatthe hydrogenated carbon filmspre pared with lower pulse bias, especially zero bias, display polymer like feature. The DLCfilms deposited with 15 kVpulsebiascontainsthehighestdensityofsp3 bonds. Thecore lev elband ( C1s) spectra of allfilmsshifttowardlow bindingenergy after4kVAr+ ion bom barding. The valenceband spectra of hydrogenated DLCfilmsarequite differentfrom thatof diamond and graphite. However, afterion bombarding, besidetwosingle peaksatabout17 0 eVand 12 5 eV(similarto graphite) ,two new sharp peaksappearatabout21 3 eVand 8 0 eV,respectively. Thepeak at8 0 eVcan beconsidertothecontribution duetothe actingofimplanted argon on C Cbondsand C Hbondsin thefilms.
关键词:
hydrogenated DLCfilms
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null
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null
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null
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D.Eylon
,
S.R.Seagle
材料科学技术（英文）
The state of Ti research, development and industry is reviewed in this article. The fifty-year anniversary of Ti technology commercialization in the USA provides an opportunity for a historical perspective. Incorporation of "information-age" tools into alloy development, processing, and production invigorates the technology. Consolidation, diversification and globalization have been transforming the Ti industry in the recent years.
关键词:
WU Chuansong
,
CAO Zhenning
,
WU Lin Harbin Institute of Technology
,
Harbin
,
China
金属学报(英文版)
A model is established to analyze three-dimensional fluid flow and heat transfer in TICweld pools with full penetration.It considers the deformation of the molten pool surfaceat the condition of full penetrated workpieees,takes the are pressure as the drivingforce of the pool surface deformation,and determines the surface configuration of weldpool based on the dynamic balance of arc pressure,pool gravity and surface tension atdeformed weld pool surface. The SIMPLER algorithm is used to calculate the fluid flowfield and temperature distribution in TIG weld pools of stainless steel workpieces.TIGwelding experiments are made to verify the validity of the model.It shows the calculatedresults by the model are in good agreement with experimental measurements. professor,Dept of Welding Engineering,Harbin Institute of Technology,Harbin 150006,China
关键词:
KEY WORDS TIG weld pool
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null
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null
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null
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null
Yanwu Xu
材料科学技术（英文）
Using mathematical plasticity theories, universal formability (UF) technology has been developed and applied in the automotive stamping engineering and production. As a formability analysis tool, this technology is the major methodology for the development of stamping expert system (solution provider) for (a) product design and feasibility analysis, (b) material automatic selection using nomograms, (c) draw die design using pre-models, and (d) UF and robustness analysis of die performance in finite element analysis (FEA) environment.
关键词:
G.Montay
,
A.Cherouat
,
A.Nussair
,
J.Lu
材料科学技术（英文）
Residual stress in coatings is the result of individual particle stress. Their effects may be either beneficial or detrimental, depending upon the magnitude, sign and distribution of the stresses with respect to the external load. Tensile stress which exceeds the elastic limit causes cracking in surface coatings or at the interface between the substrate and the coat. Compressive stress, in general, has a beneficial effect on the fatigue life, crack propagation, coating adhesion and on the durability of the top coat during service. Compressive residual stresses can increase the number of cycles before crack initiation begins through a mean stress effect. Temperature gradients which occur during solidification and subsequent cooling are the principal mode of internal stresses generation. Some parameters influence the residual stress field of both the coating and the substrate. Substrate nature, spraying temperature, thickness of the coat layer, substrate preparation (grit blasting conditions), and velocity of the splats are in the relation with the quality of the coating. In this work, we will describe the role playing by the ceramics coating elaboration on the residual stress gradient in depth of the component. The incremental hole drilling technique has been developed to determine the residual stress gradient in depth of the coat and substrate which must be used with particularly conditions. This new technology has been employed on zirconia, alumina and tungsten carbide plasma sprayed coating.
关键词:
Coating
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null
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null
,
null
LIANG Yong LI Ruiguo Institute of Metal Research
,
Academia Sinica
,
Shenyang 110015
,
ChinaInstitute of Corrosion and Protection of Metals
,
Aademia Sinica
,
Shenyang
,
110015
,
China
材料科学技术（英文）
Recent advances in laser coating technology including laser cladding,laser surface alloying and laser vapour deposition in China are reviewed in this paper.
关键词:
laser
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null
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null
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null
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null
