In which year did the single crystal blade with high nano-cavity made by steel research break through?

20 15. according to the inquiry of scientific research institutions, on 20 15, the key technology of engineering of high na DD407 single crystal blades in iron and steel research made a major breakthrough, and the yield was greatly improved. Yan Gang Gahona was restructured from one of the three domestic research institutes for developing superalloys, with profound technical accumulation.