Process optimization and mechanical property investigation of non-weldable superalloy Alloy713ELC manufactured with selective electron beam melting

Abstract

An efficient optimization method based on a support vector machine (SVM) is used to optimize multiple process parameters of selective electron beam melting (SEBM) for a non-weldable nickel-base superalloy Alloy713ELC. The global optimum condition and the near optimum conditions are extracted to fabricate SEBM samples. All the SVM optimized conditions lead to near net shaped samples with even top surfaces. The sample fabricated under the global optimum condition for sample dimension of 10 mm exhibits pore-less cross-sections, columnar grains with fine γ′ precipitates and fine substructure, a small amount of grain boundary crack and excellent room temperature tensile properties. The samples fabricated under the global optimum condition and a near optimum condition with increased beam current for sample dimension of 15 mm exhibit excellent creep properties under 980 °C. In both the two situations for sample dimensions of 10 mm and 15 mm, SEBM samples with mechanical properties superior to conventional cast alloys can be achieved by testing only 1–3 SVM optimized conditions. We demonstrate the current method is effective for optimizing SEBM process, especially when multiple parameters need to be considered simultaneously. Besides, this method can rapidly provide not only a batch of conditions leading to samples with good top surfaces but also the optimum conditions leading to good building quality and superior mechanical properties.