Badania możliwości łączenia kompozytów metalowych odlewanych odśrodkowo

Abstract

Centrifugal composite castings based on aluminium alloys belong to a group of materials with high potential for application in the automotive and aerospace industries. Their use is limited by the lack of a technology enabling the obtainment of a permanent joint ensuring safe operation. The article presents the results of preliminary surfacing and welding tests of a hybrid centrifugal composite casting based on the AlSi12 alloy and reinforced with silicon carbide (5 % by weight) and glassy carbon (5 % by weight) particles. Structural tests and the quantitative evaluation of the distribution of structural constituents indicated the possibility of the joining of such composites using the TIG welding process. It was found that overlay welds made using the filler metal having a chemical composition similar to that of the matrix could be treated as a buffer layer. The aforesaid approach should enable the joining of composite castings. The structure of the weld revealed the presence of heterogeneously distributed reinforcing phases, which was related to the gradient structure of centrifugal composite castings. The presence of the Al4C3 phase at the interface between the glassy carbon and the matrix could result in the reduction of corrosion resistance in a humid environment. The structural tests discussed in the article should be supplemented with the assessment of the mechanical properties of the joint. As a result, it will be possible to implement the technology for the welding of composite castings on an industrial scale.