Effect of Part Processing Temperature on Mechanical Properties in Electron Beam Melting

An Arcam A2 EBM system equipped with and infrared camera (IR) has been used to provide layer-by-layer feedback and detect anomalies such as voids and temperature variations during fabrication.  Further work has been performed using the IR camera to provide layer-by-layer surface temperature information that can help in studying how process temperatures affect mechanical properties of EBM-fabricated parts.  A method for obtaining accurate surface temperature measurements with the IR camera has been developed using radiation calculations, and these measurements have been used to modify builds to fabricate tensile specimens under different part temperatures.  Tensile testing, hardness testing, fracture analysis, and microstructural analysis have been performed and the results are compared against a benchmark using standard EBM process temperature parameters.  Parts fabricated under modified temperature conditions reached up to 1032MPa (±5MPa) in ultimate tensile strength and yield strength of 993MPa (±8MPa) as compared to parts built with standard processing parameters that only reached up to 988MPa (±2MPa) ultimate tensile strength and a yield strength of 878MPa (±7MPa).