[16P-T6-02] Effect of Preheating on Microstructure Evolution and Creep Properties of IN718 Processed by Laser Powder Bed Fusion
Keywords:IN718, Laser powder bed fusion, Preheating
In the laser powder bed fusion (L-PBF) method, Ar gas flows to remove fumes and quenches the specimen surface during solidification. This rapid cooling induces solidification segregation and solidification cracking. Preheating, which relieves rapid cooling and decreases residual stress would be important. In the powder bed fusion EBM, preheating is commonly used to prevent smoke and charging. However, in the L-PBF method, using preheating is not always common. This work aims to clarify the thermal behavior during the L-PBF process using preheated base plate temperatures (200degC and 600degC) for the IN718 superalloy using COMSOL simulation and experiment. The creep properties and microstructure of IN718 were found to be influenced by the preheating temperature. The specimen preheated at 600degC exhibited longer creep life and elongation than the specimen preheated at 200degC because of a lower amount of Nb segregation in the specimen preheated at 600degC during the L-PBF process.