The solidification microstructure of Fe_(70)Cr_(18)Mo_2Si_1B_9 single-roll quenched ribbons with dif- ferent rotating speed of roller and under different atmosphere conditions was investigated. Apart from usual crysta...The solidification microstructure of Fe_(70)Cr_(18)Mo_2Si_1B_9 single-roll quenched ribbons with dif- ferent rotating speed of roller and under different atmosphere conditions was investigated. Apart from usual crystallization by homogeneous and heterogeneous nucleation,it was found that α-iron cohnnnar grains with strong preferred orientation formed beneath free surface and that spheres of α-iron single coastal with a size of several μm up to 20μm,which have rarely been reported,appeared inside the ribbons.There was experirnental evidence suggesting that clusters of metal atoms formed from fluctuation in early undercooled liquid might play a role as pre-existed nuclei and,in fact,control the formation of amorphous for this alloy.展开更多
The melt spun ribbons of Al-La-Y-Ni(Fe)quaternary alloys were prepared by a single- roller melt spinning technique in vacuum.Their amorphous nature,mechanical properties and tensile fracture surface morphology were in...The melt spun ribbons of Al-La-Y-Ni(Fe)quaternary alloys were prepared by a single- roller melt spinning technique in vacuum.Their amorphous nature,mechanical properties and tensile fracture surface morphology were investigated.The experimental results show that amorphous alloys with high strength and good ductility as well as good thermal stability can be achieved in Al-La-Y-Ni(Fe)system,when the alloy contains 85—90 at.-% Al and less than 10 at.-% La+Y.The maximum tensile fracture strength(σ_f) and microhardness(HV)are as high as 760 MPa and 294 DPN,respectively.The as- quenched ribbons can be bent 180 degree without fracturing.The dominant factors for formation of amorphous Al-La-Y-Ni(Fe)are the strong attractive interaction among Al, La,Y and a decrease of melting temperature.展开更多
文摘The solidification microstructure of Fe_(70)Cr_(18)Mo_2Si_1B_9 single-roll quenched ribbons with dif- ferent rotating speed of roller and under different atmosphere conditions was investigated. Apart from usual crystallization by homogeneous and heterogeneous nucleation,it was found that α-iron cohnnnar grains with strong preferred orientation formed beneath free surface and that spheres of α-iron single coastal with a size of several μm up to 20μm,which have rarely been reported,appeared inside the ribbons.There was experirnental evidence suggesting that clusters of metal atoms formed from fluctuation in early undercooled liquid might play a role as pre-existed nuclei and,in fact,control the formation of amorphous for this alloy.
文摘The melt spun ribbons of Al-La-Y-Ni(Fe)quaternary alloys were prepared by a single- roller melt spinning technique in vacuum.Their amorphous nature,mechanical properties and tensile fracture surface morphology were investigated.The experimental results show that amorphous alloys with high strength and good ductility as well as good thermal stability can be achieved in Al-La-Y-Ni(Fe)system,when the alloy contains 85—90 at.-% Al and less than 10 at.-% La+Y.The maximum tensile fracture strength(σ_f) and microhardness(HV)are as high as 760 MPa and 294 DPN,respectively.The as- quenched ribbons can be bent 180 degree without fracturing.The dominant factors for formation of amorphous Al-La-Y-Ni(Fe)are the strong attractive interaction among Al, La,Y and a decrease of melting temperature.
