The ultrasonic energy field(UEF)-induced grain refinement mechanisms in laser powder direct energy deposition-manufactured Ti5321G alloys were systematically investigated in this study.This study focused on the interp...The ultrasonic energy field(UEF)-induced grain refinement mechanisms in laser powder direct energy deposition-manufactured Ti5321G alloys were systematically investigated in this study.This study focused on the interplay between recrystallization in the high-temperature solid deposition layers and the ultrasonic cavitation-acoustic streaming effects during molten pool solidification.A novel experimental design was developed to decouple these mechanisms by creating four distinct UEF action zones(without UEF-N,withUEF-S,with UEF-L,and with UEF-S+L)within a single-pass multilayer sample.This approach enabled the dual effects of UEF(recrystallization in solidified layers and ultrasonic cavitation-acoustic streaming effects in liquid pools)to be directly compared.The UEF significantly refined the microstructures,reducing the average grain size by 64.2%(from(399.6±28.6)to(143.1±16.1)μm)in the with UEF-S+L zone,while promoting columnar-to-equiaxed transition,with the equiaxed grain probability increasing from 11.1%(without UEF) to 53.8%.The texture intensity was reduced by approximately 52.4%and the mechanical properties were enhanced,achieving a 6.2% increase in yield strength((702.0±10.6)MPa)and 31.7%improvement in elongation.Crucially,this study revealed the synergistic effect of the dual-action mechanisms of UEF,where recrystallization and cavitation-acoustic streaming collectively enabled non-linear grain refinement.This study provides a strategy for microstructural control in additive manufacturing,eliminating the need for complex post-processing and thereby advancing the industrial application of high-performance titanium components.展开更多
基金supported by the National Key Researchand Development Program of China(No.2021YFC2801904)the Science Fund of Shandong Laboratory of Advanced Materials and Green Manufacturing at Yantai,China(No.AMGM2024F11).
文摘The ultrasonic energy field(UEF)-induced grain refinement mechanisms in laser powder direct energy deposition-manufactured Ti5321G alloys were systematically investigated in this study.This study focused on the interplay between recrystallization in the high-temperature solid deposition layers and the ultrasonic cavitation-acoustic streaming effects during molten pool solidification.A novel experimental design was developed to decouple these mechanisms by creating four distinct UEF action zones(without UEF-N,withUEF-S,with UEF-L,and with UEF-S+L)within a single-pass multilayer sample.This approach enabled the dual effects of UEF(recrystallization in solidified layers and ultrasonic cavitation-acoustic streaming effects in liquid pools)to be directly compared.The UEF significantly refined the microstructures,reducing the average grain size by 64.2%(from(399.6±28.6)to(143.1±16.1)μm)in the with UEF-S+L zone,while promoting columnar-to-equiaxed transition,with the equiaxed grain probability increasing from 11.1%(without UEF) to 53.8%.The texture intensity was reduced by approximately 52.4%and the mechanical properties were enhanced,achieving a 6.2% increase in yield strength((702.0±10.6)MPa)and 31.7%improvement in elongation.Crucially,this study revealed the synergistic effect of the dual-action mechanisms of UEF,where recrystallization and cavitation-acoustic streaming collectively enabled non-linear grain refinement.This study provides a strategy for microstructural control in additive manufacturing,eliminating the need for complex post-processing and thereby advancing the industrial application of high-performance titanium components.
