Microstructure Analysis for the Ultrasonic Fatigued Alloys using SANS

In this study, the variation of the microstructure owing to the fatigue test for some aluminum alloys and Cu-Zn alloys was investigated. Several aluminum and Cu-Zn alloy samples were prepared by ultrasonic fatigue as a function of testing time. Small angle neutron scattering (SANS) measurement was performed to investigate a signature from the nanosize pores or cracks, etc., in the sample matrix. Also, TEM work was carried out. The inhomogeneity that make the SANS pattern seems to be more than two kind; one can be the dislocations occurred during fatigue test, and the other is can be the several kinds of precipitates in the aluminum matrix. The fine precipitates maybe can grow a little cause by the heat isolated inside the sample during the fatigue test. In the case of Al1050, the sample is nearly pure aluminum with clean matrix and good ductility. So any variation of the microstructure was not observed in the ultrasonic fatigue test, so that make no difference in SANS pattern