The Experts below are selected from a list of 159 Experts worldwide ranked by ideXlab platform

Guo-quan Lu - One of the best experts on this subject based on the ideXlab platform.

  • Isothermal low cycle Fatigue behavior of nano-silver sintered single lap shear joint
    2012 13th International Conference on Electronic Packaging Technology & High Density Packaging, 2012
    Co-Authors: Xin Li, Xu Chen, Guo-quan Lu
    Abstract:

    To have a full description of the Fatigue behavior of nano-silver sintered lap shear joint, isothermal low cycle Mechanical Fatigue Test was conducted in a systematic manner over a wide range of temperatures (25 to 325°C) with the shear strain amplitude set at different values. The low cycle Fatigue behavior of the sintered lap shear joint was found to be strongly dependent on Test temperature. To investigate the temperature affection on Fatigue life, a new life prediction model based on Basquin model was developed by transforming the Fatigue strength exponent bth and Fatigue strength coefficient, efth as a function of temperature rather than numerical constants.

  • Isothermal low cycle Fatigue behavior of nano-silver sintered single lap shear joint
    2012 13th International Conference on Electronic Packaging Technology & High Density Packaging, 2012
    Co-Authors: Xin Li, Xu Chen, Guo-quan Lu
    Abstract:

    To have a full description of the Fatigue behavior of nano-silver sintered lap shear joint, isothermal low cycle Mechanical Fatigue Test was conducted in a systematic manner over a wide range of temperatures (25 to 325°C) with the shear strain amplitude set at different values. The low cycle Fatigue behavior of the sintered lap shear joint was found to be strongly dependent on Test temperature. To investigate the temperature affection on Fatigue life, a new life prediction model based on Basquin model was developed by transforming the Fatigue strength exponent bth and Fatigue strength coefficient, εfth as a function of temperature rather than numerical constants.

Johan Liu - One of the best experts on this subject based on the ideXlab platform.

  • Microstructure evolution of Sn-Zn based lead-free solder joints aged in humid atmosphere at high temperature
    Zhongguo Youse Jinshu Xuebao Chinese Journal of Nonferrous Metals, 2006
    Co-Authors: Xi Cheng Wei, Zhao Nian Cheng, Guo Kui Ju, Peng Sun, Dong Kai Shangguan, Johan Liu
    Abstract:

    The Sn-Zn based lead free solder appears to be an attractive alternative with a melting temperature relatively close to eutectic Sn-Pb. The addition of bismuth in Sn-Zn alloy improves its wettability and aluminum is beneficial to improve the oxidation resistance. The degradation of Sn-Zn based solder joints after exposed in the temperature and humid atmosphere with high pressure was studied. Three kinds of Sn-Zn system solders (Sn-9Zn, Sn-8Zn-3Bi and Sn-7Zn-Al (30 × 10 -6 )) were soldered on copper pad with a layer of Au/Ni and the specimens were stored in a pressure cooker for 96 or 192 h. The temperature and the relative humidity in the cooker were 120°C and 100% respectively. The Mechanical Fatigue Test was carried in a displacement-controlled mode to measure the low cycle Fatigue of the joints. The results show that Zn diffuses to the surface and interface while coarsening at the same time, and the coarser Zn has weak interface with β-Sn matrix and oxides form. High temperature and high humidity exposure decreases the mean life of Sn-Zn solder joints when they are subjected to 120°C and 100% relative humidity with 2.03 × 10 5 Pa pressure for 192 h.

  • Microstructural evolution of Sn-Zn based lead free solders after temperature and humid atmosphere exposure
    High Density Microsystem Design and Packaging and Component Failure Analysis, 2005 Conference on, 2005
    Co-Authors: Peng Sun, Zhao Nian Cheng, Clas Andersson, Xi Cheng Wei, Cristina Andersson, Dong Kai Shangguan, Johan Liu
    Abstract:

    The Sn-Zn based lead free solders appear to be an attractive alternative with a melting temperature that is relatively close to eutectic Sn-Pb. The addition of bismuth improves wettability of Sn-Zn alloy and aluminum is found to improve the oxidation resistance of the eutectic Sn-Zn solder. The objective of this study is to explore the degradation of Sn-Zn system solders after temperature and humid atmosphere exposure. Three kinds of Sn-Zn system solders (Sn-9Zn, Sn-8Zn-3Bi and Sn-7Zn-Al(30ppm)) were soldered on copper pad with a layer of Au/Ni and the specimens were stored in 120 degC/100% relative humidity for 96 hours or 192 hours in a pressure cooker. Zn diffused to the surface and interface while coarsening at the same time. The coarser Zn had weak interface with p-Sn matrix and oxidation was formed. The Mechanical Fatigue Test was carried in a displacement-controlled mode and the results show that high temperature humidity exposure decreases the mean life of Sn-Zn system solder joints when they are subjected to 120degC and 100% relative humidity for 192 hours after the pressure cooker Test

Gholam Hossein Farrahi - One of the best experts on this subject based on the ideXlab platform.

  • thermo Mechanical stress analysis of thermal barrier coating system considering thickness and roughness effects
    Surface & Coatings Technology, 2014
    Co-Authors: Arefe Moridi, Mohammad Azadi, Gholam Hossein Farrahi
    Abstract:

    Abstract Cast aluminium–silicon alloy, A356.0, is widely used in automotive and aerospace industries because of its outstanding Mechanical, physical, and casting properties. Thermal barrier coatings can be applied to combustion chamber to reduce fuel consumption and pollutions and also improve Fatigue life of components. The purpose of the present work is to simulate stress distribution of A356.0 under thermo-Mechanical cyclic loadings, using a two-layer elastic-visco-plastic model of ABAQUS. The results of stress–strain hysteresis loop are validated by an out of phase thermo-Mechanical Fatigue Test. Different thicknesses from 300 to 800 μm of top coat and also roughness of the interfaces are simulated to get best stress gradient. Results show that increasing top coat thickness causes stress increase. The realistic interface model is useful for identifying critical areas in stress development. Two important factors having considerable effect on development of high stress in TBC, are the severity of undulations relating to amplitude and wavelength of interface waves; and the thickness of BC layer relating to mutual positioning of either interfaces. However the realistic model has some limitations including long calculation time and difficulties of generating a suitable mesh. To diminish these limitations, after recognizing critical area, in second stage of the study, a periodic unit cell is used instead . Eight models considering different mutual positioning of interfacial asperities along with different penetration in adjoining layers are simulated and compared. Results show that detachment of the thermal barrier coating system from substrate is more probable Results show that IP positioning of mutual waves produce more severe stress but contour pattern is less likely to promote crack propagation.

Akihiko Chiba - One of the best experts on this subject based on the ideXlab platform.

  • thermo Mechanical Fatigue Test of a wrought co based alloy as potential tooling material for die casting
    Materials Science and Engineering A-structural Materials Properties Microstructure and Processing, 2014
    Co-Authors: Ning Tang, Yunping Li, Phacharaphon Tunthawiroon, Yuichiro Koizumi, Akihiko Chiba
    Abstract:

    Abstract Thermo-Mechanical Fatigue (TMF) Test of a wrought Co–Cr–Mo alloy was investigated and Co-based alloy showed superior TMF properties than the control sample of a hot work tool steel. During TMF Test, high oxidation resistance and increased hardness were observed in the Co-based alloy in contrast to the low oxidation resistance and decreased hardness in the tool steel. The γ-phase-to-e-phase transformation of the Co-based alloy was considered as the main hardening factor during the TMF Test.

Xin Li - One of the best experts on this subject based on the ideXlab platform.

  • Isothermal low cycle Fatigue behavior of nano-silver sintered single lap shear joint
    2012 13th International Conference on Electronic Packaging Technology & High Density Packaging, 2012
    Co-Authors: Xin Li, Xu Chen, Guo-quan Lu
    Abstract:

    To have a full description of the Fatigue behavior of nano-silver sintered lap shear joint, isothermal low cycle Mechanical Fatigue Test was conducted in a systematic manner over a wide range of temperatures (25 to 325°C) with the shear strain amplitude set at different values. The low cycle Fatigue behavior of the sintered lap shear joint was found to be strongly dependent on Test temperature. To investigate the temperature affection on Fatigue life, a new life prediction model based on Basquin model was developed by transforming the Fatigue strength exponent bth and Fatigue strength coefficient, efth as a function of temperature rather than numerical constants.

  • Isothermal low cycle Fatigue behavior of nano-silver sintered single lap shear joint
    2012 13th International Conference on Electronic Packaging Technology & High Density Packaging, 2012
    Co-Authors: Xin Li, Xu Chen, Guo-quan Lu
    Abstract:

    To have a full description of the Fatigue behavior of nano-silver sintered lap shear joint, isothermal low cycle Mechanical Fatigue Test was conducted in a systematic manner over a wide range of temperatures (25 to 325°C) with the shear strain amplitude set at different values. The low cycle Fatigue behavior of the sintered lap shear joint was found to be strongly dependent on Test temperature. To investigate the temperature affection on Fatigue life, a new life prediction model based on Basquin model was developed by transforming the Fatigue strength exponent bth and Fatigue strength coefficient, εfth as a function of temperature rather than numerical constants.