摘要
The effect of boron addition(0.010,0.015,and 0.020 wt.%)on the microstructure and mechanical properties of an additively manufactured superalloy was examined.The as-built microstructure was investigated by scanning electron microscopy and transmission electron microscopy.The results demonstrate that boron precipitates as M_(3)B_(2)boride at the grain boundary.The increase in boron content increases the amount ofγ/γ′eutectic and the size and fraction of M_(3)B_(2)boride.Boron creates nanoscale fine borides at grain boundaries,which significantly reinforces grain boundaries.The mechanical property analysis indicated that the addition of boron improved the tensile ductility at 760℃and stress rupture properties at 760℃/780 MPa.However,with the excessive addition of boron,the mechanical property was reduced.
基金
The authors are grateful for the financial support provided by the National Key Research and Development Program of China(No.2021YFB3702500)
National Science and Technology Major Project of China(Y2019-VII-0011-0151,2019-VII-0019-0161).
