Papers by Author: Jue Zhong

Abstract: In order to understand the solidification behavior in the semi-continuous casting process of 7B50 aluminum alloy, a thermo-mechanical model for the analysis of 7B50 aluminum alloy solidification process is presented, this model considering liquid-solid phase-change effects for the solidification alloy. The thermal contact conductance between the mould wall and the ingot, the convective heat transfer coefficient are taken into account in the model. The distribution of temperature and stress in the process of semi-continuous casting of 7B50aluminum alloy are analyzed in three-dimensional finite element methods based on the above models. The variation of casting speed to influence the temperature and stress of the ingot in the process of semi-continuous casting is studied.

Abstract: The microstructures of Al-0.2Sc and Al-0.2Sc-0.12Zr alloys have been investigated.The results show that Al3Sc and Al3(Sc1-xZrx) dispersoids exist in as-rolled Al-0.2Sc and Al-0.2Sc-0.12Zr alloy respectively, and their orientation is (001)α║(001)dispersoid, [010]α║[010]dispersoid.The Al3Sc particles in as-rolled Al-0.2Sc were precipitated from hot rolling process, while the larger Al3(Sc1-xZrx) particles in as-rolled Al-0.2Sc-0.12Zr from the solidification, and the small particles also from hot rolling process. There is segregation of Sc and Zr in the Al3(Sc1-xZrx) dispersoid, and Sc is rich in the outside shell while Zr rich in the core of the particles. It is believed that the grain and subgrain boundaries can be pinned by the Al3Sc particles when annealed after cold-rolling, and this may lead to restricting the recrystallization of the Sc-containing alloys.And it’s not until the dissolution of Al3Sc that the recrystallization can happen in this kind of alloys.

Abstract: The present paper outlines the effect of small addition of Sc,Ag and Mg on the ageing characteristics and microstructural evolution in some microalloyed Al alloys,such as Al-Cu-Mg, Al-Ag and Al-Li alloys.Small quantities of these microalloying elements can modify the ageing characteristics of these alloys,and significant changes have been found in their microstructural evolution after small microalloying element additions. The observed effects are explained in terms of the atomic behaviour during the early ageing stage,and one of the key factors governing this effect is Sc/Vacancy mechanism.

Abstract: To find out the effect mechanism of technological parameters on the performance of fiber coupler, the relationship between the technological parameters and the optical performance is investigated by using a six-axes optical fiber coupler machine as experimental setup. It is discovered that the technological parameters such as drawing speed and fused temperature have a great effect on optical performance of fibre coupler. The fused region and taper region of fiber coupler are tested with scanning electron microscope (SEM). It is discovered that there are crystalline grains in the fused region. And the crystalline grains decrease while drawing speed increase. In the taper region, there are micro cracks. And the cracks are more obvious while drawing speed increases. When the fused temperature is above some point (here is 1350
), the micro cracks in the taper region disappear and the optical performance of fiber coupler is the highest at this time.

Abstract: Vertical section features in bonding point were produced by ion-sputter thinning, and were tested by using TEM-F30. Lift-off characteristics at the interface of Ultrasonic bond are observed by using SEM (JSM-6360LV). Results show that thickness of Au/Al atomic diffusion interface was about 500 Nanometer under ultrasonic and thermal energy. Ultrasonic vibration activates dislocations at metal crystal lattice. Fracture morphology of lift-off interface was dimples. Tensile fracture appeared by pull-test not in bonded interface but in basis material, and bonded strength at interface was enhanced by diffused atom from the other side.