The influence of the precipitation on the accuracy of residual stress ultrasonic measurement was studied in this paper

the7 xxx aluminum alloy base material was kept warm for 2

4

6

8 hours at 200 degrees and then made into experimental samples. The stress constant K

propagation time of ultrasonic wave in zero stress medium t

0

and ultrasonic attenuation of the samples were tested and the exact influence of the precipitation on two calculation parameters

K and t

0

was analysed. After analysis

there were no significant changes of K

t

0

and ultrasonic attenuation in the four groups of samples with obvious difference in precipitated phase content. This showed that the accuracy of residual stress ultrasonic measurement was not affected by the precipitation of 7 xxx aluminum alloy.