Análisis cinético y estadístico de la precipitación en una aleación de Cu-0,49Co-0,44Ti, mediante microcalorimetría y medidas de microdureza

E. Donoso; G. Díaz

doi:10.3989/revmetalm.0926

Authors

E. Donoso Universidad de Chile, Facultad de Ciencias Físicas y Matemáticas, Departamento de Ciencia de los Materiales
G. Díaz Universidad de Chile, Facultad de Ciencias Físicas y Matemáticas, Departamento de Ciencia de los Materiales

DOI:

https://doi.org/10.3989/revmetalm.0926

Keywords:

Copper, Cu-Co-Ti, Precipitation, Microhardness, Weibull statistics

Abstract

Starting with a solid solution of Cu-0,49Co-0,44Ti tempered from 1173 K, the kinetics of precipitation of atoms of cobalt and titanium was studied by means of differential scanning calorimetry (DSC). The analysis of the calorimetric curves show the presence of an exothermal reaction that is attributed to the formation of particles of CoTi in the copper matrix. The energy of activation of the reaction was estimated by means of a modified method of Kissinger. The kinetic parameters were estimated with the use of the formalism of Johnson-Mehl-Avrami. On the other hand, a statistical analysis of the process of precipitation was performed by measuring the microhardness Vickers, employing a Weibull probability distribution function. Using minimum square method the Weibull parameters were estimated. The goodness of fit was analyzed by using the Chi square test with a condidence level of 95 percent. Increasing the aging time, for the sam annealing temperature, theWeibull modulus increase too, which may be attributed to precipitation of CoTi phase.

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