Fig. 5: Processing effects on plastic strain, microstructure, and hardness.

A Distributions of the BCC full-width half-maximum (FWHM) through the sample measured at room temperature after building each sections which correlates with B high and low regions of microhardness measured along the sample centerline. C The time-resolved FWHM at point 1 increases during the transformation from FCC to BCC on cooling following the deposition of section 1 and D decreases when reheated during the deposition of section 2. E IR data at a height of 48 mm during building of section 3 shows a location with final cooling going through the FCC to BCC transformation at M_s which correlates to a region of high FWHM and F a region at 34 mm, where the final thermal cycle heats to just over A_s, causing annealing and lower final FHWM. G The BCC grain structure for regions with high FWHM indicates lath martensite with H high kernel average misorientation, indicating high dislocation density. I Areas with low FWHM have a recrystallized grain structure (scale is 200 µm) and J very low kernel average misorientation.