Serrated flow of Al-Li single crystals was investigated under different aging conditions,temperatures(T)and strain rates(ε).The results show that dynamic strain aging(DSA)of solute Li atoms alone is not strong enough...Serrated flow of Al-Li single crystals was investigated under different aging conditions,temperatures(T)and strain rates(ε).The results show that dynamic strain aging(DSA)of solute Li atoms alone is not strong enough to make the serrated flow at solid solution state.The occurrence of the serrated flow is related to the shearing ofδ'particles.Critical strain of serration can change normally or inversely with T and e,which indicates the serration in Al-Li alloys is a thermally activated process.A proposed mechanism for the occurrence of the serration is that mobile dislocations are pinned when they cross the shearedδ'particles that might be dissolved during deformation,thus induce the serrated flow in the Al-Li single crystal.展开更多
Using magnetic decoration technique,the distribution of magnetic flux in power-melting-processed Y-Ba-Cu-O superconductor has been studied in an applied field of 200G at 64K.The decoration patterns indicate that twin ...Using magnetic decoration technique,the distribution of magnetic flux in power-melting-processed Y-Ba-Cu-O superconductor has been studied in an applied field of 200G at 64K.The decoration patterns indicate that twin boundaries act as strong flux pinning sites and the nonsuperconducting Y_(2)BaCuO_(5)(211)inclusions provide pinning sites in their vicinity by inducing lattice distortion.Chain-like vortex distribution,distorted hexagonal flux line lattice and anisotropic vortices have been observed.展开更多
基金Supported by the National Natural Science Foundation of China。
文摘Serrated flow of Al-Li single crystals was investigated under different aging conditions,temperatures(T)and strain rates(ε).The results show that dynamic strain aging(DSA)of solute Li atoms alone is not strong enough to make the serrated flow at solid solution state.The occurrence of the serrated flow is related to the shearing ofδ'particles.Critical strain of serration can change normally or inversely with T and e,which indicates the serration in Al-Li alloys is a thermally activated process.A proposed mechanism for the occurrence of the serration is that mobile dislocations are pinned when they cross the shearedδ'particles that might be dissolved during deformation,thus induce the serrated flow in the Al-Li single crystal.
基金Supported by the National Natural Science Foundation of Chinathe Chinese National Center for R&D on Superconductivity.
文摘Using magnetic decoration technique,the distribution of magnetic flux in power-melting-processed Y-Ba-Cu-O superconductor has been studied in an applied field of 200G at 64K.The decoration patterns indicate that twin boundaries act as strong flux pinning sites and the nonsuperconducting Y_(2)BaCuO_(5)(211)inclusions provide pinning sites in their vicinity by inducing lattice distortion.Chain-like vortex distribution,distorted hexagonal flux line lattice and anisotropic vortices have been observed.
