Improved tensile strength of welded AlSi10Mg alloys by using laser metal deposition

Laser metal deposition process was introduced to join AlSi10Mg alloys fabricated by powder bed fusion-laser beam/metal to improve the tensile strength of laser welded joints. The size and the porosity of the hydrogen pores in the weld seam are significantly reduced by laser metal deposition welding. The ultimate tensile strength of the welded joint by using laser metal deposition reaches 318.8 MPa, and the microhardness of the weld seam ranges from 99.5 to 105.4 HV. Compared with single-pass welding, the ultimate tensile strength and hardness are increased by 60.6% and 27.6%. This is mainly attributed to the reduced porosity, refined α-Al structures and increased connectivity of the Si-rich networks of the weld seam achieved by laser metal deposition welding.