METHOD FOR DETERMINING MICROHETEROGENEITY OF A MELT OF A SAMPLE OF A MULTICOMPONENT METAL ALLOY Russian patent published in 2023 - IPC G01N11/00 G01N27/14 G01N25/02 

FIELD: technical physics; metallurgy.

SUBSTANCE: method is proposed for determining the microheterogeneity of a melt of a sample of a multicomponent metal alloy by obtaining the temperature dependences of the kinematic viscosity ν_i(T_i) during heating and cooling of the molten sample of this alloy in a certain temperature range, obtaining discrete values of the parameters ν_i(T_i) in form of electrical signals U_i. According to the claimed method, the value of the threshold of the second derivative d²(U_i)_thr is set, the transformations associated with the change in the microheterogeneous state, with the change in the activation energy E_A of the viscous flow, are determined. Graphs ln(ν_i) of the reciprocal temperature 1/T in form ln(ν_i)=ϕ(1/T_i) are charted. Data in form of electrical signals U_i~ln(ν_i) is differentiated twice to get d²(U_i). It is compared with threshold d²(U_i)_thr: if value d²(U_i) is less than d²(U_i)_thr, then the anomaly in the dependence ν_i(T_i) is considered to be absent, and when d²(U_i) is greater than the threshold signal d²(U_i)_thr, there is an anomaly, which allows to conclude that there is a structural transformation in the melt. A synchronous graph is built for magnitude U_i~ln(ν_i)=ϕ(1/T_i), that is approximated by straight lines reflecting the course of ln(ν_i)=ϕ(1/T_i) before and after the anomaly. Value of the slope of these lines in form of angles α₁ and α₂ is determined. In the absence of an anomaly, these angles are equal; in presence of an anomaly, angle α₁ is more than angle α₂, and the presence of an anomaly is accompanied by a decrease in the activation energy E_A1 of the viscous flow of an inhomogeneous melt, which is proportional to tg α₁, up to the value of E_A2 proportional to tg α₂. After that, a conclusion is made about transition of the tested melt into a more homogeneous state when it is heated above the temperature of the anomaly T_i=T_an.

EFFECT: reduced wear of equipment, clarity and reliability of determining the temperature anomaly of the sample, even in the absence of hysteresis for dependencies ν_i(T_i), which makes it possible to determine the temperature of anomaly T_an using the temperature dependence ν_i(T_i) obtained only during the sample heating mode.

1 cl, 4 dwg