Analiza zmian trwałości zmęczeniowej i mikrostruktury poliamidu w funkcji stanu cieplnego formy i obróbki cieplnej

Experimental and physical analysis of influence of surface mould temperature and thermal treatment of unstabilised specimens on fatigue strength and physical microstructure of polyamid 6 (Tarnamid T-27) is presented. The number of cycles to failure of specimen and three structural parameters (namely, degree of crystallinity, cross dimensions of crystallites and density) were taken as a measure of processes occuving in a specimen. The method of limited base was employed in statistical calculations. In determining structural parameters the method of X-ray radiography and the method of displacement were used. The principles of choice of preparations for X-ray measurements from the specimens showing large dispersion of fatigue life were specified. Photometric diagrams of Debye-Scherrer X-ray photographs were analysed. It was found that heating of the mould surface is not only indispensable manipulation in moulding process of polyamid to preserve its dimension stability but is also desired to improve the fatigue properties.