Extended Data Fig. 10: Impact toughness.
From: High-strength Damascus steel by additive manufacturing
a, The absorbed energies of subsized V-notch Charpy specimens at three different temperatures of −180 °C, 22 °C and 200 °C. The inset shows the geometry of the used subsized specimens. Charpy specimens were machined along the laser scan direction of the DED sample with the B direction normal to the layers and the b direction parallel to the layers. The values shown in the graph are an average of three specimens at 22 °C and two specimens at −180 °C and 200 °C. b, The values of the absorbed energy in joules in the Charpy V-notch impact testing carried out on subsized specimens shown in the inset in a. Two different normalizing factors are used to convert the results of the subsized specimen to standard specimen (55 × 10 × 8 mm3): the fracture area B × b and the fracture volume B × b2 (see, for example, refs. 33,34,35). It is noted that such normalizing factors are material dependent and there is no literature available on the selection of normalizing factors for additively manufactured maraging steels. The converted values presented in this table should therefore only be regarded as a rough estimate of the impact toughness on standard samples. Nevertheless, the Fe19Ni5Ti (wt%) samples investigated in this study show a high impact toughness compared with 4.9 J (standard V-notch samples) of laser-powder-bed-fusion-produced 18Ni-300 maraging steel in the aged condition (5 h at 480 °C)36.
