The Cu-24 Pb-x Sn(wt%)(x=0,2,4,6)alloys with Pb-rich second-phase particles(SPPs)in different shapes show obviously differently mechanical and self-lubricating properties.The influence of the SPPs’shape difference on...The Cu-24 Pb-x Sn(wt%)(x=0,2,4,6)alloys with Pb-rich second-phase particles(SPPs)in different shapes show obviously differently mechanical and self-lubricating properties.The influence of the SPPs’shape difference on the alloys’mechanical and self-lubricating properties was revealed.Cu-24 Pb alloy with continuously netty SPPs shows much more intensive stick-slip phenomenon during dry sliding than the other three alloys with independently rodlike SPPs.That is mainly due to insufficient lubrication resulted by the netty SPPs’splitting matrix.With the SPPs transforming from netty to rodlike shape under the addition of Sn,the stick-slip phenomenon was notably weakened,which was proven to be related to the higher self-lubricating property of alloys with rodlike SPPs.Simultaneously,the simultaneous increase of ductility and tensile strength was observed in the Cu-24 Pb-x Sn alloys with increasing Sn content,which is because the netty SPPs’splitting behavior will be weakened with them replaced by the rodlike SPPs.展开更多
The development of ultrastrong maraging stainless steels(MSSs)is always in high demand.However,traditional high-strength MSSs generally exhibit early plastic instability with a low uniform strain since the precipitate...The development of ultrastrong maraging stainless steels(MSSs)is always in high demand.However,traditional high-strength MSSs generally exhibit early plastic instability with a low uniform strain since the precipitated nanoparticles are non-coherent with the body-centered-cubic(BCC)lath martensitic matrix.Here,we design a novel ultrahigh strength MSS(Fe-5.30 Cr-13.47 Ni-3.10 Al-1.22 Mo-0.50 W-0.23 Nb-0.03 C-0.005 B,wt.%)using a cluster formula approach.A fabulous microstructure consisting of a uniform distribution of high-density coherent B2-Ni Al nanoprecipitates(3-5 nm)in BCC martensitic matrix was successfully obtained.This alloy has not only an exceedingly high ultimate tensile strength of 2.0 GPa,but also a decent uniform elongation of 4.2%-5.1%,which is almost triple of the value observed in existing MSSs.We present an in-depth discussion on the origins of ultrahigh strength and uniform plastic strain in the new alloy to validate our design strategy and further offer a new pathway to exploit highperformance MSSs.展开更多
基金supported financially by the National Key Research and Development Program of China(Nos.2016YFB0301303 and 2017YFB0306105)the National Natural Science Foundation of China(Nos.51871041,51771040and51690163)the Fundamental Research Funds for the Central Universities of China(No.DUT17JC44).
文摘The Cu-24 Pb-x Sn(wt%)(x=0,2,4,6)alloys with Pb-rich second-phase particles(SPPs)in different shapes show obviously differently mechanical and self-lubricating properties.The influence of the SPPs’shape difference on the alloys’mechanical and self-lubricating properties was revealed.Cu-24 Pb alloy with continuously netty SPPs shows much more intensive stick-slip phenomenon during dry sliding than the other three alloys with independently rodlike SPPs.That is mainly due to insufficient lubrication resulted by the netty SPPs’splitting matrix.With the SPPs transforming from netty to rodlike shape under the addition of Sn,the stick-slip phenomenon was notably weakened,which was proven to be related to the higher self-lubricating property of alloys with rodlike SPPs.Simultaneously,the simultaneous increase of ductility and tensile strength was observed in the Cu-24 Pb-x Sn alloys with increasing Sn content,which is because the netty SPPs’splitting behavior will be weakened with them replaced by the rodlike SPPs.
基金supported by the National Natural Science Foundation of China[grant numbers 91860108,U1867201]Natural Science Foundation of Liaoning Province of China[grant number 2019-KF-05-01]the Fundamental Research Funds for the Central Universities[grant number DUT19LAB01]。
文摘The development of ultrastrong maraging stainless steels(MSSs)is always in high demand.However,traditional high-strength MSSs generally exhibit early plastic instability with a low uniform strain since the precipitated nanoparticles are non-coherent with the body-centered-cubic(BCC)lath martensitic matrix.Here,we design a novel ultrahigh strength MSS(Fe-5.30 Cr-13.47 Ni-3.10 Al-1.22 Mo-0.50 W-0.23 Nb-0.03 C-0.005 B,wt.%)using a cluster formula approach.A fabulous microstructure consisting of a uniform distribution of high-density coherent B2-Ni Al nanoprecipitates(3-5 nm)in BCC martensitic matrix was successfully obtained.This alloy has not only an exceedingly high ultimate tensile strength of 2.0 GPa,but also a decent uniform elongation of 4.2%-5.1%,which is almost triple of the value observed in existing MSSs.We present an in-depth discussion on the origins of ultrahigh strength and uniform plastic strain in the new alloy to validate our design strategy and further offer a new pathway to exploit highperformance MSSs.
