Abstract
In the paper is presented the time and temperature influences of thermic treatment upon the mechanic properties of alloy ATSi 5 Cu7Mg used to cast the thermic motor pistons. From the tests of determining the properties of TSi5Cu7+MgNi(Fe) treated thermically and centreated, for the casting of the pistons of thermic motors with firing through spark was shown that:
- The thermic treatment of hardening through precipitation, the treatment that wants to obtain some maximum mechanical properties based on a solid solution supersaturated by alloy elements (Ea) in Al, it is proved to be useless, because of the following phenomena;
- The pistons of thermic motors, during functioning, pass over the SOLVUS CURVE temperature (the solubility curve in a solid state of Ea in Al), and the obtain effect through T.T. is annulated;
- The annulment of the obtained effects after T.T., of hardness through precipitation, depends on temperature and on the maintaing time at this temperature
Keywords: thermic treatment, mechanic properties, thermic motor pistons, alloy