New insight into laser butt welded nonporous SiCp/2A14Al joint: Interfaces, precipitation phase and mechanical properties

Highlights: • SiCp/2A14Al welded joints without pores and cracks were prepared via laser welding (LW). • Four kinds of Cu-, Mg-, Mn- and Si- rich nanometer precipitation phases are distributed in Al matrix. • Ternary Al-Si-C films were formed in-situ at the edge of unmelted SiC particles in welding zone. • The maximum tensile strength of single laser butt joint reaches 174 MPa. SiC reinforced 2×××Al metal matrix composites are high performance aviation composite material. However, the great gap in thermal expansion coefficient, melting point and thermal conductivity between SiC and Al matrix result in poor laser weldability of SiCp/2×××Al joints. Here, SiCp/2A14Al welded joints without cracks were prepared via laser welding (LW). Results showed that ternary Al-Si-C films were formed in-situ at the edge of unmelted SiC particles in fusion zone. Four kinds of Cu-, Mg-, Mn- and Si- rich nanometer precipitation phases were distributed in Al matrix and had clean interface of (002)_AlCuMgSi//(−220) _AlCu. The tensile strength of single laser butt joint reached 159 MPa, and the pre-induction preheating further improved the joint strength to 174 MPa. Through this study, in-situ formation ternary Al-Si-C films and coherent interface was studied that may provide an in-situ clean interface design window for improving mechanical properties of SiCP/2×××Al joint by laser welding.