Fig. 1

Photo of each typical specimen. a The length of radial direction is 50 mm, tangential direction is 100 mm, and the thickness of longitudinal direction is 1.5, 3.0 and 5.0 mm. b The thickness of longitudinal direction is 1.5, 3.0 and 5.0 mm. c The thickness of longitudinal direction is 1.5 mm and the diameter is 10 mm. d Grain size is 0.020–0.075, 0.075–0.150, 0.15–0.25, 0.25–0.50 and 0.50–1.00 mm