Study On The Thermoelectric Power Of Pb-Sn Alloy Melt Under AC Magnetic Field

Researchers perform the influence of alternating current(AC)electromagnetic field on the nucleation of melt,as well as the solidification behavior,improving the mechanical properties.The short-range orders of melt affect the nucleation process by some results of liquid metal.As the melt presents the relative high temperature,it is difficult to directly observe and measure the melt structure.However,the observation and measurement of short-range orders in melt help us to understand the nucleation further.As sensitive physical parameter,thermoelectric power can be used to indicate the melt structure,as well as the nucleation process during the AC electromagnetic field.The thermoelectric power measurement is used to predict the melt structured during the productive solidification in electromagnetic field.The thermoelectric power of Pb-27%Sn and Sn-22%Pb alloys under AC electromagnetic field are studied to indicate the short-range orders of melt,combining with the solidification microsturctures.The main conclusions of the research are as follows:(1)AC magnetic field changes the melt structure and thermoelectric power of melt.Thermoelectric power presents a violent oscillation during the magnetic field treating.After stopping the magnetic field,thermoelectric power is larger than the initial data,which needs some time to recover into the stable data.(2)The thermoelectric power variation attributes to the magnetic intensity,melt temperature,the temperature gradient and the probe distance under the AC magnetic field.With the increased magnetic intensity,the thermoelectric power variation and recovery increase.Under the same magnetic intensity,the thermoelectric power variation increases and then decrease with the increased melt temperature,and the thermoelectric power variation positively depends on the recovery time,which is also obtained under the different temperature gradient.Further,the probe distance also Effects the thermoelectric power variation.(3)AC magnetic field changes the primary phases and decreases the size of primary phases,improving the disorder growth.Meanwhile,AC magnetic field improves the uniformity distribution of phases.AC magnetic field treatment makes the segregation of primary phases under the constant temperature heat preservation.(4)When the superheat is 100?,the primary phase size in the AC magnetic field has the positive relationship with the thermoelectric power variation.