The work presents the test result of the influence of cooling rate on the microstructure of AZ91 alloy, Vickers micro-hardness and Brinell
hardness. Studies cooling and crystallization of AZ91 alloy was cast into the ceramic shells pre-heated to 180 ° C and then air-cooled at
ambient temperature or intensively super cooled in the liquid coolant. The TDA method was applied to record and characterize the thermal
effect resulting from the phase transformations occurring during the crystallization of AZ91 alloy. The kinetics and dynamics of the
thermal processes of crystallization of AZ91 alloy in the ceramic shells were determined. Metallographic tests were performed with the
use of an optical microscope. A comparison of these test results with the thermal effect recorded by way of the TDA method was made.
Influence of cooling rate of AZ91 on HV0, 01 micro-hardness and Brinell hardness alloy was examined.
The paper examines the contemporary discussion of the concept of ‘national hero’. As the subject of analysis interpretations of the role of Roman Dmowski, the leader of Polish nationalist movement in the first half of 20th century, in the contemporary political and historical discussion in Poland was chosen. On that example the way in which political life is changing the previous assessment and meaning of the ‘national hero’ is observed.