Conventional strategies to strengthen alloys are usually accompanied by drastic sacrifice in ductility,which is known as the strength-ductility trade-off.New metallurgical processing approaches are required to defeat ...Conventional strategies to strengthen alloys are usually accompanied by drastic sacrifice in ductility,which is known as the strength-ductility trade-off.New metallurgical processing approaches are required to defeat this longstanding dilemma.Here we report a novel solid-state powder manufacturing route to overcome this challenge enabling the architecting of a complex multiphase constituent composite using readily available metal powder as a feedstock.The materials design philosophy is successfully verified in a system mixing conventional austenitic stainless steel and ferritic steel powder and consolidating it by hot isostatic pressing.Significant strengthening and work hardenability are achieved at no expense of ductility compared to the ferrite and austenite on their own.Such extraordinary strength-ductility synergy is attributed to the well-architected compositional gradients across different phases resulting in soft and hard regions at the scale of the original powder without sharp interfaces.Accordingly,plasticity progresses from soft to hard regions during mechanical loading,which is the key to mitigating the deformation incompatibility and enabling remarkable ductility.Our study provides a new concept for materials design with synergistic properties that used to be trade-offs in conventional materials,which is applicable to a broad range of material systems with unprecedented multifunctionality.展开更多
Post-heat treatment is a necessary and important step for additive-manufactured products to relieve residual stress and to further improve mechanical performance.In this work,the heat treatment strat-egy for Inconel 7...Post-heat treatment is a necessary and important step for additive-manufactured products to relieve residual stress and to further improve mechanical performance.In this work,the heat treatment strat-egy for Inconel 718 superalloy fabricated by rolling-assisted laser-directed energy deposition(L-DED)has been designed and systematically investigated for the first time.The results show that the designed ho-mogenization heat treatment at 1080℃ for 10 min can effectively dissolve most of the detrimental Lave phases existing in the rolling-assisted L-DED samples.Meanwhile,it results in a homogenous grain struc-ture through static recrystallization,while maintaining a similar prior-refined grain size of∼8μm.On this basis,a high number density ofγ″andγ′precipitates appear in the microstructure after applying a subsequent double-aging heat treatment.The optimized microstructure through such effective post-heat treatment designed in this work has led to a significant increase in material strength at both the room and elevated temperatures while maintaining good ductility.展开更多
基金financially supported by the National Key R&D Program of China(No.2023YFB3712703)the Engineering and Physical Sciences Research Council(EPSRC)Rolls-Royce Plc.Michael Preuss would like to acknowledge the start-up fund from Monash University.
文摘Conventional strategies to strengthen alloys are usually accompanied by drastic sacrifice in ductility,which is known as the strength-ductility trade-off.New metallurgical processing approaches are required to defeat this longstanding dilemma.Here we report a novel solid-state powder manufacturing route to overcome this challenge enabling the architecting of a complex multiphase constituent composite using readily available metal powder as a feedstock.The materials design philosophy is successfully verified in a system mixing conventional austenitic stainless steel and ferritic steel powder and consolidating it by hot isostatic pressing.Significant strengthening and work hardenability are achieved at no expense of ductility compared to the ferrite and austenite on their own.Such extraordinary strength-ductility synergy is attributed to the well-architected compositional gradients across different phases resulting in soft and hard regions at the scale of the original powder without sharp interfaces.Accordingly,plasticity progresses from soft to hard regions during mechanical loading,which is the key to mitigating the deformation incompatibility and enabling remarkable ductility.Our study provides a new concept for materials design with synergistic properties that used to be trade-offs in conventional materials,which is applicable to a broad range of material systems with unprecedented multifunctionality.
文摘Post-heat treatment is a necessary and important step for additive-manufactured products to relieve residual stress and to further improve mechanical performance.In this work,the heat treatment strat-egy for Inconel 718 superalloy fabricated by rolling-assisted laser-directed energy deposition(L-DED)has been designed and systematically investigated for the first time.The results show that the designed ho-mogenization heat treatment at 1080℃ for 10 min can effectively dissolve most of the detrimental Lave phases existing in the rolling-assisted L-DED samples.Meanwhile,it results in a homogenous grain struc-ture through static recrystallization,while maintaining a similar prior-refined grain size of∼8μm.On this basis,a high number density ofγ″andγ′precipitates appear in the microstructure after applying a subsequent double-aging heat treatment.The optimized microstructure through such effective post-heat treatment designed in this work has led to a significant increase in material strength at both the room and elevated temperatures while maintaining good ductility.
