Identifying of boron in FSW steel samples through SIMS technology

抄録

  Improvement of bainitic hardenability is outstanding feature of the boron addition into iron and steel. It is well established that a hardenability peak is accomplished when the concentration of boron is about several to several tens of weight ppm. In the previous study, resistive anode encoder (RAE) of the secondary ion mass spectroscopy (SIMS) was used to map the distribution of ppm of boron in iron and steel with the overall quantification using cluster-polyatomic secondary ion species for both impurity, I_i and matrix, I_m to reduce the matrix effect. The quantification of the boron was proposed by retrospective depth profile from the RAE boron map. In this study, the relative sensitivity factors (RSFs) and calibration curve of the standard reference materials were examined and calculated to identify the dissolved boron concentration which might be originated from poly crystal boron nitride (PCBN) tool in friction stir welding (FSW) for steel samples. Retrospective depth profile and linear regression of the calibration curve provides the boron quantification in FSW steel samples. Dark contrast areas on the FSW steel samples were indentified higher boron concentration than bright areas. It is accounted that the combination of ¹¹B¹⁶O₂ and ⁵⁶Fe¹⁶O as for I_i / I_m is a useful method of SIMS quantification from boron image in iron and steel with minimal number of standard reference materials.