Atom probe tomography and nano secondary ion mass spectroscopy investigation of the segregation of boron at austenite grain boundaries in 0.5 wt.% carbon steels

Abstract

The grain boundary segregation of boron atoms in high strength low alloy steels containing 50 ppm boron was accomplished using atom probe tomography (APT) and nano-beam secondary ion mass spectroscopy (SIMS). The formation of boro-carbides under an excessive addition of boron to the steels was identified through the SIMS and TEM. The APT was performed in order to evaluate the composition of the alloying elements, such as, boron and carbon, segregated at prior austenite grain boundaries. The boron contents at the prior austenite grain boundaries were approximately 1.7 ± 0.2 at.%, which was approximately 70 times more than the amount of boron added to the steels.

Atomic worlds: Current state and future of atom probe tomography in geoscience

“…Developments in correlative microscopy, particularly the use of combined physical and chemical characterization techniques such as TEM, TKD, and EBSD[58], along with Nano-Computed Tomography (CT), to identify and characterize regions of interest prior to APM analysis are also likely to play an important part in an advanced methodology for nanoscale geoscience. There is also potential for the integration of high spatial resolution compositional mapping tools such as sub-micron SIMS (nanoSIMS)[59,60] and SEM-based time-of-flight secondary ion mass spectrometry (TOF-SIMS)[61] to identify regions of interest at the submicrometre scale. In the geoscience field, characterization of needle-shaped specimens by transmission electron microscopy…”

Coupling Secondary Ion Mass Spectrometry and Atom Probe Tomography for Atomic Diffusion and Segregation Measurements

“…Furthermore, segregation coefficients and segregation activation energy measurements are used to predict the influence of processing and aging on material properties. APT measurements give access to 1D, 2D, and 3D atomic distributions, allowing quantitative concentration measurements in extended defects such as GBs and dislocations (Blavette et al, 1999; Seol et al, 2011, 2013). For example, Figure 9a shows a 2D Pt concentration map in a polycrystalline Ni 2 Si layer.…”

Effect of phosphorous and boron addition on microstructural evolution and Charpy impact properties of high-phosphorous-containing plain carbon steels

“…In general, B is distributed on austenite grain boundaries, and helps to form low-temperature transformation microstructures by stabilizing austenites, thereby providing positive effects in improving strength and toughness simultaneously [13,[26][27][28]. Among the 550 1C-treated steels, bainites mixed with degenerated pearlites are well developed in the 2PB-5 and 5PB-5 steels, and their grain size is smaller and their volume fraction is higher than in the 2P-5 and 5P-5 steels.…”