Defect-based additive manufactured creep performance evaluation via small punch test

Suffering from creep and defects, thin-walled tubes and heat-resistant components produced by additive manufacturing (AM) technology and laser repair were prone to failure. To quantify the creep damage caused by AM defects in the deposited and ultrasonic micro-forging treated (UMFT) Hastelloy X, uniaxial creep and small punch creep (SPC) tests were conducted. Additionally, the surface defects of SPC specimens were visualized and quantified using image capture technology. The defect sensitivity of the AM alloy was analyzed using various mathematical and statistical methods. Based on the traditional SPC model, the AM defect parameters were introduced. A new SPC deformation model was proposed according to the experimental results and AM defect characteristic. Therefore, a new creep life prediction model was proposed, considering the defect parameters, based on modified Monkman-Grant (MMG) model. This model exhibited good prediction accuracy and enabled the prediction of AM materials containing defects.