Butt joining of 5A02 aluminum alloy to 304 stainless steel sheets was conducted using gas tungsten arc welding process with Al-12%Si （wt.%, the same below） and Zn-15%Al flux-cored filler wires. The effects of gap wi...Butt joining of 5A02 aluminum alloy to 304 stainless steel sheets was conducted using gas tungsten arc welding process with Al-12%Si （wt.%, the same below） and Zn-15%Al flux-cored filler wires. The effects of gap width and groove in steel side on the microstructure and tensile strength of the resultant joints were investigated. For the joint made with 0 mm-wide gap and without groove in steel side, severe incomplete brazing zone occurred along the steel side and bottom surfaces, and consequently seriously deteriorated the joint strength. However, presetting 1.5 mm-wide gap or with groove in steel side could promote the wetting of molten filler metal on the laying surfaces, and then significantly enhance the resultant joint strength. Moreover, post-weld heat treatment could further improve the tensile strength of the joints. During tensile testing, the specimens from the joints made with AI-12%Si flux-cored filler wire fractured through the weld or interracial layer, but those from the heat-treated joints made with Zn-15%AI flux-cored filler wire fractured in the aluminum base metal.展开更多
The effects of parallel and angular butt designs with different gap widths on the microstructure and mechanical properties of the resultant magnesium joints in gas tungsten arc welding were investigated. The experimen...The effects of parallel and angular butt designs with different gap widths on the microstructure and mechanical properties of the resultant magnesium joints in gas tungsten arc welding were investigated. The experimental results displayed that the tensile strength of the joint made with angular butt joint and 0.3 ram-wide gap reached 266 MPa, the joint fractured through the heat-affected zone or base metal during tensile testing, and the microstructure examination showed that no macropore appeared in the fusion zone. However, macropores in diameter of larger than 200 micron occurred for other joint designs, the tensile strength of the resultant joints decreased, and the joints fractured through the fusion zone during tensile testing. The fracture surfaces were examined by scanning electron microscopy and the microhardness distribution in the joints was measured by using a Vickers microhardness tester.展开更多
The band structures of a new two-dimensional triangle-shaped array geometry of 4340 steel cylinders of square cross section in an epoxy resin were studied by the plane-wave expansion and supercell calculation method. ...The band structures of a new two-dimensional triangle-shaped array geometry of 4340 steel cylinders of square cross section in an epoxy resin were studied by the plane-wave expansion and supercell calculation method. The band gaps of this type of phononic crystals with different defects were calculated such as defect-free, 60° crystal linear defect states, 120° crystal linear defect states, and 180° crystal linear defect states. It was found that the band gap will emerge in different linear defects of the phononic crystals and the bandwidth of linear defect states is larger than that of the free-defect crystal by about 2.14 times within the filling fraction F = 0.1-0.85. In addition, the influence of the filling fraction on the relative width of the minimum band gap is discussed.展开更多
It directly affects the inner and outer aesthesis, wind noise and safety of the vehicle to the BIW width dimensional consistency. In this paper, the body in white （BIW） width dimensional consistency control methods ...It directly affects the inner and outer aesthesis, wind noise and safety of the vehicle to the BIW width dimensional consistency. In this paper, the body in white （BIW） width dimensional consistency control methods had been carried on the concrete discussion and research. So the mechanism of virtual size parts were introduced in detail and the mechanism of the width of the BIW were analyzed. And this paper recommended the partial tolerance design method, DESIGN GAP design method and overlapping parts structure design method. Then the applications of these methods were explained to develop new product. The result that practiced control strategy to new vehicle practice showed： the BIW width dimensional consistency can be controlled within ±1.0 mm. The control strategy can realize the robust design of the new product dimension and enrich the company dimensional database.展开更多
基金supported by the National Natural Science Foundation of China(No.50904012/ E041607)Natural Science Foundation of Liaoning Province(No.20092152)
文摘Butt joining of 5A02 aluminum alloy to 304 stainless steel sheets was conducted using gas tungsten arc welding process with Al-12%Si （wt.%, the same below） and Zn-15%Al flux-cored filler wires. The effects of gap width and groove in steel side on the microstructure and tensile strength of the resultant joints were investigated. For the joint made with 0 mm-wide gap and without groove in steel side, severe incomplete brazing zone occurred along the steel side and bottom surfaces, and consequently seriously deteriorated the joint strength. However, presetting 1.5 mm-wide gap or with groove in steel side could promote the wetting of molten filler metal on the laying surfaces, and then significantly enhance the resultant joint strength. Moreover, post-weld heat treatment could further improve the tensile strength of the joints. During tensile testing, the specimens from the joints made with AI-12%Si flux-cored filler wire fractured through the weld or interracial layer, but those from the heat-treated joints made with Zn-15%AI flux-cored filler wire fractured in the aluminum base metal.
基金supported by the State Key Lab of Advanced Welding and Joining,Harbin Institute of Technology (Project No.09009)
文摘The effects of parallel and angular butt designs with different gap widths on the microstructure and mechanical properties of the resultant magnesium joints in gas tungsten arc welding were investigated. The experimental results displayed that the tensile strength of the joint made with angular butt joint and 0.3 ram-wide gap reached 266 MPa, the joint fractured through the heat-affected zone or base metal during tensile testing, and the microstructure examination showed that no macropore appeared in the fusion zone. However, macropores in diameter of larger than 200 micron occurred for other joint designs, the tensile strength of the resultant joints decreased, and the joints fractured through the fusion zone during tensile testing. The fracture surfaces were examined by scanning electron microscopy and the microhardness distribution in the joints was measured by using a Vickers microhardness tester.
基金Project supported by the National Natural Science Foundation of China (Grant Nos. 10764005 and 11164034)the New Century Training Program Foundation for Talents from the Ministry of Education of China (Grant No. NCET-08-0926)
文摘The band structures of a new two-dimensional triangle-shaped array geometry of 4340 steel cylinders of square cross section in an epoxy resin were studied by the plane-wave expansion and supercell calculation method. The band gaps of this type of phononic crystals with different defects were calculated such as defect-free, 60° crystal linear defect states, 120° crystal linear defect states, and 180° crystal linear defect states. It was found that the band gap will emerge in different linear defects of the phononic crystals and the bandwidth of linear defect states is larger than that of the free-defect crystal by about 2.14 times within the filling fraction F = 0.1-0.85. In addition, the influence of the filling fraction on the relative width of the minimum band gap is discussed.
文摘It directly affects the inner and outer aesthesis, wind noise and safety of the vehicle to the BIW width dimensional consistency. In this paper, the body in white （BIW） width dimensional consistency control methods had been carried on the concrete discussion and research. So the mechanism of virtual size parts were introduced in detail and the mechanism of the width of the BIW were analyzed. And this paper recommended the partial tolerance design method, DESIGN GAP design method and overlapping parts structure design method. Then the applications of these methods were explained to develop new product. The result that practiced control strategy to new vehicle practice showed： the BIW width dimensional consistency can be controlled within ±1.0 mm. The control strategy can realize the robust design of the new product dimension and enrich the company dimensional database.
