A. G. Liu
,
X.F. Wang
,
L.P. Wang
,
S. Y. Wang
,
B. Y. Tang and P.K. Chu 1) Advanced Welding Production Technology National Key Laboratory
,
HIT
,
Harbin 150001
,
China 2) Department of Physics and Material Science
,
City University of Hong Kong
,
83 Tat Chee Avenue
,
Kowloon
,
Hong Kang
,
China
金属学报(英文版)
Plasma immersion ion implantation (PIII), unrestricted by sight-light process, is considered a proper method for inner surface strengthening. Two-dimensional simulation oj inner surface PIII process of cylindrical bores were carried out in this paper using cold plasma fluid model, and influence of the bore's dimension on impact energy, retained dose and uniformity of inner surface were investigated.
关键词:
plasma immersion ion implantation
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null
,
null
,
null
C. Q. Wang
,
X. J. Zha
,
C. Q. Zhang
,
S. Q. Yang
,
C. Z. Wang( 1)National Lab of Advanced Welding Technology
,
HIT
,
Harbin 150001
,
China 2)Shanghai Institute of Metallurgy
,
Chinese Academy of Science
,
Shanghai 200050
,
China)
金属学报(英文版)
Solder joint reliability is one of critical problems detemining whether Sirface Mount Technology (SMT) can be used in the prohotion of important electronic products. Optimizing solder joint shape is one of effective ways to improve SMT solder joint reliability.In this paper. based on the theorem of minimum potential energy, an energy model of 3 - D solder joint shape is established,and the forma- tion of solder joint is numerically simulated by Surface Ecolver program. On the basis of the prediction of SMT solder joint shape,the mechanical model of analyzing solder joint reliability is established. An elasto - plasto - creep mateial model and its mechanical constitutive equaton are established for SnPb solder alloy, and the stress/strain response of SMT solder joint under thermal cyclical loabing is ana- lyzed with nonlinear 3 - D FEM. The fatigue life of solder joint is predicted according to Coffin- Manson fatigue life model. An integrated system for Predicting and analyzing SMT solder joint shape and reliability(PSAR) is developed.The system can analyze efficiently SMT solder joint reliability with the variation of structural parameters in the joint and give the optimal structure.
关键词:
SMT
,
null
,
null
,
null
S. J. Chen
,
S. Y. Yin
,
L. Feng and L. Y. Li( 1) School of Materials Science and Engineering
,
Beijing Polytechnic University
,
Beijing 100022
,
China 2)National Key Laboratory of Advanced Welding Production Technology
,
HIT
,
Harbin 150001
,
China)
金属学报(英文版)
Based on the existing component models in the Pspice software package, a combined model for Insulat- ed the Bipolar Transistor (IGBT) is established, in which a non - linear is introduced to represent the parasitic capacitance. Using this model, computerized simulation is conducted for the FB - ZVZCS - PWM soft - ewitching converter,the switching and energy-transferring characteristics of the components are analyzed.The simulation results are testified by experiments.It is proved that by abopting appropriate models,computerized simulation becomes an effective tool for investigation of arc welding inverter power source.
关键词:
arc welding inverter
,
null
,
null
S. Y. Yin
,
L. Feng
,
J. Z. Ding and S. J. Chan( 1) Beijing Polytechnic University
,
Beijing 100022
,
China 2) National Key Laboratory of Advanced Wdlding Production Technology
,
HIT
,
Harbin 150001
,
China)
金属学报(英文版)
Based on the theory of stability of the liquid metal under the action of surface tension,a physical mod- el is established for the mechanisms of the bead formation deferct' humping', which is generated during high - speed welding.A boundary function is introduced to correct the model,theoretical results got by the model correspond well with the experimental phenomena. A two - dimensional conducting model is adoopted in the simulation of the temperature field during high - speed welding.Finally, the factors acting upon the stability of liquid metal are analyzed.
关键词:
high - speed welding
,
null
,
null
X. Y. Li
,
X. T. Tian and H. C. Zhu( 1)Weldng Division
,
Beijing Polytechnic University
,
Beijing 100022
,
China 2)National ho. of Advanced Welding Technology
,
HIT
,
Harbin 150001
,
China)
金属学报(英文版)
Mismatching is one of the basic characteristics of welded joints.Overmatched welded joint with a crack in hard weld is simplified as a cracked body of CCP type SHS (a hard bar sandwiched between two soft material with a crier perallel to the interface ) in this paper.Effects of mechanical heterogeneity on fatigue crack growth and crack closure of this model are studied by experimental and elastic - plastic finite element methods. It is found that, residual plastic deformation remaining in the wake of a growing crack tip, which cases crack closure,is affected the plastic deformation in adjacent soft mate- rial near by the crack tip. Both the shape of crack tip plastic zone and stress distribution ahead of crack tip in heterogeneous cracked body are different from that of homogeneous one. Crack closure (open- ing) loads are estimated by investigating the changes of crack tip opening displacement during fatigue loading, and a new model of crack oening process is presented. Because of the difference in the effect of mechanical heterogeneity on displacement of non - fatigue crack and fatigue crack, conventional CTOD can not reflect the real deformation at crack tip of SHS specimens.
关键词:
welded joint
,
null
,
null
,
null
J. T. Niu
,
Y. H. Tian
,
B. Y. Li
,
J. J. Xu
,
L.M. Liu (National Key Laboratory of Advanced welding Production Technology
,
HIT
,
Harbin 150001
,
China)
金属学报(英文版)
Tensile strength of diffusion welded joint of aluminum matrix composite is very low due to its poor weld- ability.In this paper, solution and age treatments were conducted on the welded joint of Al2O3p/ 6061Al composite subjected to diffusion welding using Gleeble 1500 machine, and ensile strength and microstructure of welded joint aged at175℃ were measured and analyzed respectively, Results showed that aging precipitation of welded joint is promoted effectively because of redistribution of reinforcement and a few number of dislocations in the matrix of weld zone resulting from welding pressure,and hence tensile strength of welded joint is increased significantly after aging treatment.
关键词:
aluminum matrix composite
,
null
,
null
J. T. Niu
,
L. M. Liu
,
J. P. Zhai
,
J. Yu
,
X. M. Zhang (National Key Laboratory of Advanced Welding Production Technology
,
HIT
,
Harbin 750001
,
China)
金属学报(英文版)
Effects of diffusion welding parameters on strength of welded joint based on particle reinforced alumini- um matrix composite Al2O3p/6061Al were studied by comparing with aluminium matrix alloy,Mecha- nism for the loss of joint strength was analyzed.It was pointed out that the key processing parameters affecting the strength of joint was the welding temperature.The high quality joint can be successfully obtained with appropriate diffusion welding parameters.
关键词:
particle reinforced aluminium matrix composite
,
null
,
null
R. P. Liu
,
Z. J. Dong and Y. H. Wei( 1)Harbin Research Institute of Welding
,
Harbin 150080
,
China 2)National Key Laboratory of Advanced Welding Production Technology
,
HIT
,
Harbin 150001
,
China)
金属学报(英文版)
This paper has analyzed the influences of the heat input of welding arc, the latent heat of solidifica- tion,fluid flow of liquid metal on the heat conductivity pertaining to welding solidification crack of stainless steels. As a result,two - dimensional heat conduction models with prescribed heat flux mov- ing along the the have been developed that can simulate welding arc, convection and radiation heat loss from top and bottom surfaces of the workpiece. Finally, the finite element model was used to ana- lyze and calculate the temperature field.
关键词:
stainless steel
,
null
,
null
,
null
Y. H. Wei
,
R. P. Liu and Z. J. Dong( 1) National Key Laboratory of Advanced Welding Production Technology
,
HIT
,
Harbin 150001
,
China 2) Harbin Research institute of Welding
,
Harbin 150080
,
China)
金属学报(英文版)
This paper analyzed the characteristics of welding solidification crack of stainless steels,and clearly re- vealed the the of the deformation in the molten - the pool and the solidification shrinkage on the stress - strain fields in the trail of molten - weld pool.Moreover, rheologic properties of the alloys in solid - liquid zone were also obtained by measuring the hading and unloading deform curves of the steels.As a result, a numerical model for simulation of stress - strain distributions of welding solidifi- cation crack was developed. On the basis of the model,the thesis simulated the driving force of solidifi- cation crack of stainless steels, that is, stress - strain fields in the trail of molten-weld pool with fi- nite element method.
关键词:
welding solidification crack
,
null
,
null
,
null
,
null
S. Q. Yang
,
Z. Dong
,
J. C. Yan and J. B. Ju( National Key Laboratory of Advanced Welding Production Technology
,
HIT
,
Harbin 150001
,
China)
金属学报(英文版)
The energy conversion during ultrasonic plastic welding is analyzed on the basis of the theory of vis- coelastic mechanics,.The temperature field and the temperature change of the ABS specimen with ener- gy director during ultrasonic welding is simulated with finite element method(FEM). In the simu- lation process,the melting of the energy energy is also considered. The calculation results are in good agreement with the temperature measurement results, which proves that the simulation results are reli- able.
关键词:
ultrasonic plastic welding
,
null
,
null
