November_December_2021_AMP_Digital

A D V A N C E D M A T E R I A L S & P R O C E S S E S | N O V E M B E R / D E C E M B E R 2 0 2 1 3 2 cipitates, whether they be titanium, niobium carbonitrides, or other ele- ments (Fig. 3). A 10 x 10 grid is estab- lished, and 100 EDS maps are auto- matically collected over an area of 58.1 x 58.1 µm. The process takes 5 min- utes of manual setup and 17 hours of automated work that can be completed overnight. VISUALIZING THE DATA Using Thermo Scientific Avizo2D with Thermo Scientific Velox software and Thermo Scientific Maps Software, (S)TEMandEDS imagesareautomatical- ly recorded as part of the workflow and transformed into particle data, where the precipitates are segmented and la- beled (Fig. 4). Precipitates analyzed at the nanometer scale are combined with results from other techniques inves- tigating large precipitates (>500 nm). Together, these methods provide a comprehensive picture of both small and large precipitates across the sam- ple. This information is then used to generate histograms showing the size distribution of each precipitate, provid- ing the final information OCAS’ custom- ers need for their samples of interest (Fig. 5). FASTER, MORE ACCURATE DATA Using APW, the morphology, size distribution, and chemical composition of steel sample precipitates can be cap- tured in less than 18 hours, almost all of which involves automated, unattend- ed work. APW enables up to 4000 pre- cipitates (at this pixel resolution) to be studied at a time, representing 20 times what was possible with OCAS’ previ- ous workflow and leading to more sta- tistically relevant data. It helps OCAS provide the precise information their customers need to produce steel for dif- ferent applications. In addition to en- abling the acquisition of more accurate data over a larger sample area, APW im- proves productivity, enabling techni- cians to analyze more samples in less time and freeing them up to perform other types of analyses while the auto- mated work is in process. CONCLUSION Using Thermo Scientific’s APW, which combines (S)TEM images with EDS mapping, OCAS has improved the efficiency and accuracy of its precipi- tate analyses. With this workflow, the research center can now quickly obtain the morphology, size distribution, and chemical composition of up to 4000 pre- cipitates per sample. It can also accu- rately analyze the distribution of both small and large precipitates over a de- fined area to obtain the comprehensive data needed during the steel R&D pro- cess. ~AM&P Note: Co-author is Hui (Maggie) Shi, research engineer at OCAS, Material Characterization and Testing Center, Belgium, hui.shi@arcelormittal.com , www.ocas.be . For more information: Roger Madd- alena, market development manager for metals, Thermo Fisher Scientif- ic, Materials and Structural Analy- sis, 412.287.8472, roger.maddalena@ thermofisher.com, www.thermofisher . com. Fig. 5 — Comparison of size distribution of Ti-rich precipitates between two samples. This includes about 4000 precipitates over 30 nm in size from the original 2.837 nm resolution scan, in addition to an extrapolation of a second scan at higher resolution over a smaller area to characterize the smaller precipitates. Thus, the APW can evaluate the full-size range of precipitates to compare the difference between samples.