Magnetization associated with reversible phase transformation or rearrangement of martensite variants of two kinds of shape memory alloys under the coupling of tensile stress were investigated.One is the austenitic Ni...Magnetization associated with reversible phase transformation or rearrangement of martensite variants of two kinds of shape memory alloys under the coupling of tensile stress were investigated.One is the austenitic Ni_(46)Mn_(28)Ga_(20)Co_(3)Cu_(3)micro wire with the [001] preferred orientation,which exhibits enhanced cyclic stability and large fully recoverable strain(> 8%) due to the stress-induced reversible martensitic transformation at room temperature.The other is the Ni_(54)Mn_(24)Ga_(22)microwire with ferromagnetic martensitic phase,which has preferential orientation and also exhibits large tensile strain.Based on the improved mechanical properties,the strain-magnetization effect of the two kinds of microwire under the coupling of orthogonal magnetic field and tensile stress was performed and the results indicate that the magnetization decreases with the increase of tensile strains.Furthermore,the magnetization mechanism related to the magnetostructural evolution under stress-magnetic coupling was discussed.This study provides a new way for smart magnetic microwires for novel non-contact and non-destructive detection.展开更多
In order to improve the low ductility of nanostructured materials, a layered and nanostructured （LN） 304 SS （stainless steel） is prepared from warm co-rolled 304 SS pre-treated by surface mechanical attrition trea...In order to improve the low ductility of nanostructured materials, a layered and nanostructured （LN） 304 SS （stainless steel） is prepared from warm co-rolled 304 SS pre-treated by surface mechanical attrition treatment. The microstructure and mechanical properties, as well as strain hardening, are analyzed in details. The LN steels ex- hibit both high strength and large ductility resulting from good strain hardening behaviors. The strain hardening can be subdivided into two stages, which involves a multiple cracking along interlaminar at the first stage and a strain-in- duced martensite （SIM） transformation at the second stage. The SIM transformation of nanocrystallines and ultrafine grains induces a larger work hardening exponent by the formation of nanoscaled martensite phase. The effect of grain size on the transformation dynamics is discussed.展开更多
基金financially supported by the National High Technology Research and Development Program of China (No.2015AA034101)the State Key Laboratory for Advanced Metals and Materials (No.2018Z-26)+1 种基金the National Natural Science Foundation of China (No.51771121)the Science and Technology Commission of Shanghai Municipality (No.20ZR1437500)。
文摘Magnetization associated with reversible phase transformation or rearrangement of martensite variants of two kinds of shape memory alloys under the coupling of tensile stress were investigated.One is the austenitic Ni_(46)Mn_(28)Ga_(20)Co_(3)Cu_(3)micro wire with the [001] preferred orientation,which exhibits enhanced cyclic stability and large fully recoverable strain(> 8%) due to the stress-induced reversible martensitic transformation at room temperature.The other is the Ni_(54)Mn_(24)Ga_(22)microwire with ferromagnetic martensitic phase,which has preferential orientation and also exhibits large tensile strain.Based on the improved mechanical properties,the strain-magnetization effect of the two kinds of microwire under the coupling of orthogonal magnetic field and tensile stress was performed and the results indicate that the magnetization decreases with the increase of tensile strains.Furthermore,the magnetization mechanism related to the magnetostructural evolution under stress-magnetic coupling was discussed.This study provides a new way for smart magnetic microwires for novel non-contact and non-destructive detection.
基金Item Sponsored by National Natural Science Foundation of China(11202134,51271123)Funds from Shanghai Municipal Education Commission of China(5313310202)
文摘In order to improve the low ductility of nanostructured materials, a layered and nanostructured （LN） 304 SS （stainless steel） is prepared from warm co-rolled 304 SS pre-treated by surface mechanical attrition treatment. The microstructure and mechanical properties, as well as strain hardening, are analyzed in details. The LN steels ex- hibit both high strength and large ductility resulting from good strain hardening behaviors. The strain hardening can be subdivided into two stages, which involves a multiple cracking along interlaminar at the first stage and a strain-in- duced martensite （SIM） transformation at the second stage. The SIM transformation of nanocrystallines and ultrafine grains induces a larger work hardening exponent by the formation of nanoscaled martensite phase. The effect of grain size on the transformation dynamics is discussed.
