EFFECT OF IMPURITIES ON THE INTERNAL FRICTION SPECTRUM OF MAGNESIUM AFTER PLASTIC DEFORMATION

We have studied the impurity effect on the internal friction spectrum, with two different samples magnesium 4N and magnesium 6N containing zinc and iron : - for the sample 4N we observe a broad peak depending on the oscillation strain amplitude : this peak shifts towards low temperature when the amplitude increases. - for the sample 6N containing zinc and iron, the internal friction spectrum is different form the one of the 6N sample previously mentioned. After annealing at 250 K we observe, at low strain amplitude, besides the B1and B2peaks, two other peaks situated around 100 and 150 K. But at a high strain amplitude we find the two peaks B1and B2as in the 6N sample. After annealing at 500 K the B1and B2peak are not observed but a large peak appears which shifts towards low temperature with increasing εmThis peak is specific on thermomechanical unpinning of dislocations

DISLOCATIONS POINT DEFECTS INTERACTIONS IN MAGNESIUM

The interactions between dislocations and point defects have been studied in magnesium containing 100 p.p.m. of impurity atoms. The experiments where conducted on one hand by measuring the ultrasonic attenuation changes due to a bias stress and on the other hand by measuring the internal friction on a torsion pendulum working at 2 Hz

Toughness prediction in functionally graded Al6061/SiCp composites produced by roll-bonding

Functionally graded aluminum matrix composites (FGAMC) are new advanced materials with promising applications due to their unique characteristics in which composite nature is combined with graded structure