Underwater friction stir welding of 2219 aluminum alloy was carried out in order to further improve the joint performances by varying welding temperature history.The results indicated that the tensile strength of the ...Underwater friction stir welding of 2219 aluminum alloy was carried out in order to further improve the joint performances by varying welding temperature history.The results indicated that the tensile strength of the joint can be improved from 324 MPa by external water cooling action in normal to 341 MPa.However,the plasticity of the joint is deteriorated.The underwater joint tends to fracture at the interface between the weld nugget zone and the thermal mechanically affected zone on the advancing side during tensile test,which is significantly different from the normal joint.展开更多
In this paper, we perform a numerical simulation of the cavitating flow around an underwater hemispherical-head slender body running at a high speed. For the first time, the slip boundary condition is introduced into ...In this paper, we perform a numerical simulation of the cavitating flow around an underwater hemispherical-head slender body running at a high speed. For the first time, the slip boundary condition is introduced into this problem, and we find that the slip boundary condition has a big influence on the cavitation in the flow-separation zone. By simulating the cavitating flow under different cavitation numbers, we demonstrate that the slip boundary condition can effectively reduce the intensity of cavitation, as represented by the length of cavitation bubbles. The present paper provides a new method for utilization of new surface materials to control the cavitation on the underwater moving objects.展开更多
基金Project (2010CB731704) supported by the National Basic Research Program of ChinaProject (2006BAF04B09) supported by the NationalKey Technology Research and Development Program of ChinaProject supported by the Program of Excellent Team in Harbin Instituteof Technology,China
文摘Underwater friction stir welding of 2219 aluminum alloy was carried out in order to further improve the joint performances by varying welding temperature history.The results indicated that the tensile strength of the joint can be improved from 324 MPa by external water cooling action in normal to 341 MPa.However,the plasticity of the joint is deteriorated.The underwater joint tends to fracture at the interface between the weld nugget zone and the thermal mechanically affected zone on the advancing side during tensile test,which is significantly different from the normal joint.
基金the National Natural Science Foundation of China(Grant No.11172001)
文摘In this paper, we perform a numerical simulation of the cavitating flow around an underwater hemispherical-head slender body running at a high speed. For the first time, the slip boundary condition is introduced into this problem, and we find that the slip boundary condition has a big influence on the cavitation in the flow-separation zone. By simulating the cavitating flow under different cavitation numbers, we demonstrate that the slip boundary condition can effectively reduce the intensity of cavitation, as represented by the length of cavitation bubbles. The present paper provides a new method for utilization of new surface materials to control the cavitation on the underwater moving objects.
