In the alloy systems of face-centred cube(FCC)structure,the diffusivites of some solute atomsare several orders of magnitude more than those of the matrix atoms,such as Au and Ag in Pb,S in Ni,as well as B in γ-Fe.Ma...In the alloy systems of face-centred cube(FCC)structure,the diffusivites of some solute atomsare several orders of magnitude more than those of the matrix atoms,such as Au and Ag in Pb,S in Ni,as well as B in γ-Fe.Many people think that these solute atoms with anomalouslyfast diffusivities diffuse as interstitial atoms.So far this theory has been widely used.For ex-ample,the latest edition of Metal Reference Book says,about diffusion in metals,that somesolutes "may dissolve interstitially,at least in part,and diffuse by an interstitial-type process.展开更多
The Portevin-Le Chatelier （PLC） effect in the Nimonic 263 superalloy was investigated by tensile test at a wide temperature ranges from 293 to 1033 K and strain rates between 0.1 and 6.25 × 10^-6 s-1. Simple bi...The Portevin-Le Chatelier （PLC） effect in the Nimonic 263 superalloy was investigated by tensile test at a wide temperature ranges from 293 to 1033 K and strain rates between 0.1 and 6.25 × 10^-6 s-1. Simple binary alloys Ni- 0.4C, Ni-24Cr and Ni-5（8）Mo were also tested in order to identify which elements were responsible for the PLC effect in the Nimonic 263 alloy. The results demonstrated that for Nimonic 263 alloy, PLC effect occurred at certain temperatures and low strain rates. Normal PLC effect exhibiting type-A and -（A ＋ B） serrations was attributed to the enhanced solute diffusion with increasing temperature, while inverse PLC effect with type-C serration was caused by unlocking process. The activation energy for the normal PLC effect was calculated to be 68 kJ/mol, and diffusion of substitutional solutes such as Cr and Mo was identified to be responsible for the PLC effect. In comparison with the PLC effect in simple binary alloys, solute atmospheres formed by different kinds of atoms in Nimonic 263 alloy work more effectively, increasing locking strength and corresponding mean stress drop magnitude.展开更多
文摘In the alloy systems of face-centred cube(FCC)structure,the diffusivites of some solute atomsare several orders of magnitude more than those of the matrix atoms,such as Au and Ag in Pb,S in Ni,as well as B in γ-Fe.Many people think that these solute atoms with anomalouslyfast diffusivities diffuse as interstitial atoms.So far this theory has been widely used.For ex-ample,the latest edition of Metal Reference Book says,about diffusion in metals,that somesolutes "may dissolve interstitially,at least in part,and diffuse by an interstitial-type process.
基金financially supported by‘‘Hundreds of Talents Project’’National Basic Research Program of China(No.2010CB631206)(Nos.51171179,51128101 and 51271174)
文摘The Portevin-Le Chatelier （PLC） effect in the Nimonic 263 superalloy was investigated by tensile test at a wide temperature ranges from 293 to 1033 K and strain rates between 0.1 and 6.25 × 10^-6 s-1. Simple binary alloys Ni- 0.4C, Ni-24Cr and Ni-5（8）Mo were also tested in order to identify which elements were responsible for the PLC effect in the Nimonic 263 alloy. The results demonstrated that for Nimonic 263 alloy, PLC effect occurred at certain temperatures and low strain rates. Normal PLC effect exhibiting type-A and -（A ＋ B） serrations was attributed to the enhanced solute diffusion with increasing temperature, while inverse PLC effect with type-C serration was caused by unlocking process. The activation energy for the normal PLC effect was calculated to be 68 kJ/mol, and diffusion of substitutional solutes such as Cr and Mo was identified to be responsible for the PLC effect. In comparison with the PLC effect in simple binary alloys, solute atmospheres formed by different kinds of atoms in Nimonic 263 alloy work more effectively, increasing locking strength and corresponding mean stress drop magnitude.
基金This work was supported by the cooperation project between Shanghai Jiao Tong University and Huawei Technologies Co.,Ltd.,Chinathe Major Science and Technology Projects of Yunnan Science and Technology Department,China(No.202102AB080009)Xiao-qin ZENG would also like to acknowledge the support of the Xiao-qin ZENG Expert Workstation in Yunnan Province,China(No.202005AF150059).
