A new type X-ray microbeam equipment which is capable of three-dimensional oscillation at an X-ray radiation position was used to measure the residual stress of pure iron powder and bending plate specimens as well as that in the vicinity of fatigue crack tip of 1/2 CT specimen.
The results obtained are summerized as follows.
(1) Diffraction profiles of pure iron powder with φ0.02-0.03μm particle size obtained by the present microbeam technique in the beam area of 80μm in diamether and measuring time more than 800sec showed Kα1 and Kα2 peaks clearly, so that these profiles are good enough for stress measurement.
(2) The measured stress of pure iron powder with φ10-25μm particle size in the beam area of 80μm in diameter was not equal to 0MPa. The measured stress varied greatly and was independent of measuring time.
(3) The measured stress of pure iron powder with φ0.02-0.03μm particle size in the beam area of 80μm in diameter was almost 1MPa, which shows the good accuracy of this X-ray microbeam equipment.
(4) The relation between the X-ray measured stress and the mechanically applied stress showed good agreement.
(5) The distribution of residual stress at the vicinity of fatigue crack tip showed that the residual stress at the fatigue crack tip was compression and the residual stress in front of crack tip was tension. This tensile residual stress in front of crack tip existed in the area from 0.02mm to 2mm.
(6) The above results show that the present equipment is advantageous in the investigation of local stress, shortening the measuring time without sacrificing the accuracy.
