Impact of B-Doping on Microstructures and Reinforcement of Solidified GH600 Alloy Melted by Vacuum Induction

GH600-alloy,an advanced aero-engine material,was reinforced by B-doping in vacuum induction melting and by solidification.The influence of the B-content on the microstructures,phases and mechanical properties of the B-doped GH600-alloy was investigated with scanning electron microscopy and tensile strength measurement.The results show that depending on B-content,B-doping had a major impact.To be specific,as the B-content increased from 0.02%(wt) to 0.082%,the size and density of γ-precipitation-phase cluster significantly increased,the borides granular-grains were gradually replaced by borides nano-rods at grai6 n boundaries;the tensile plasticity changed in a rapid increase-decrease manner,peaking at 0.05%.In tensile measurement of the sample with a B-content above 0.05%,cleavage easily formed,particularly at the precipitate-phase boundary,propagated and finally,resulted in cracks and/or fractures because of the rapidly decreased tensile plasticity,and that accounts for the fracture mechanism.