Three-dimensional stress distribution of surplus assembled 7050Al alloy ring and plug determined by neutron diffraction

The hoop, radial and axial stress and strain distribution of surplus assembled 7050Al alloy ring and plus were investigated by neutron diffraction method. The measured results from crystal planes (200) and (311) are coincided with the data obtained by analytical calculation and international standard sample experiment. The discontinuous stress and strain at the interference of ring and plug can be clearly shown by the neutron diffraction method. Monte Carlo method was used to simulate the neutron diffraction process to reduce the deviation of the stress at the surface. The results show that the measured accuracy can be improved when the slits are substituted by the radial collimation. Compared the results obtained from (311) and (200) with analytical calculation, it reveals that the stress distribution among crystal planes will cause system deviation. Therefore the experiment accuracy may be further improved if the inner plane stress could be evaluated. The results also indicate that the strain accuracy will be affected by microstress and texture, and the gauge volume should be reduced as small as possible at the region where the stress distribution is steep.