A near infrared thermal imager has been employed for temperature measurements (build
part surfaces) in the powder-based electron beam additive manufacturing (EBAM) process. A
methodology has also been developed to analyze temperature distributions and history around
the melting scan area. The temperature profiles along the beam scanning clearly show the
moving source of heat phenomenon, with the peak temperature reaching over 2000 °C (for Ti6Al-4V) followed by extremely rapid cooling opposite to the beam scanning direction, except a
slow-cooling portion corresponding to the liquidus-solidus range. The build surface temperatures
and the melt pool sizes, in the localized electron beam scanning area, were studied at various
configurations, e.g., different build heights, also with or without an overhang.Mechanical Engineerin
