Investigation of the feasibility of online laser-induced breakdown spectroscopy for elemental analysis of compositionally graded alloy parts during their fabrication

Abstract

In this study we have demonstrated the feasibility of in situ and online laser induced breakdown spectroscopy (LIBS) analysis during compositionally graded metal part synthesis by the additive manufacturing technique. Chromium bronze and stainless steel 410 powders were deposited by coaxial laser cladding to produce the metal part with a chemical composition gradient. Different areas at the cladding spot (melt pool, solid clad, and powder jet) were sampled by LIBS in order to improve elemental determination results. Both melt pool and solidified clad LIBS sampling provided comparable analytical results due to a homogeneous elemental distribution in the clad. An analysis of metal powder flow during the additive manufacturing process was also carried out but poor analysis results were achieved due to the low reproducibility of the LIBS signals. For the first time the transition zone between two pure components in the compositionally graded alloy was quantified online utilizing LIBS measurements.