2017 | AFC ACCOMPLISHMENTS 99 Figure 2. Microstructure of the 106ZY large rods, a) As extruded rod, b) After, four cold rolling steps, with a thickness reduction of 40% at each step. A very fine and elongated grain structure formed after cold rolling. Accomplishments A large CM08 ball milling machine was used at Oak Ridge National Laboratory (ORNL) to produce ~four kilograms of 106ZY powder.Two master ODS rods of this material (250mm in length and ~22mm in diameter) were prepared by extru- sion at 1100ºC, with the extrusion can, extruded bars and final ODS 106ZY rods are shown in Figure 1. The two rods exhibited very similar properties, with hardness values ~300HV, and good tensile strength and ductility up to 600ºC. Industrial pilgering was applied to the two rods to initiate tube production. In addition, thin 0.4mm foils were fabricated by cold rolling from 3mm thick 106ZY plates to assess the alloy deformability and determine the impact of cold rolling on the alloy microstructure. It was determined that the material hardness values had to be less than 350HV to fabricate a tube by pilgering (cold rolling). As can be seen in Figure 2, a very fine and elongated grain structure was observed for the 106ZY foils, ~100nm in size, to compare with the micrometer grain size for the as extruded plates.This nano-grain structure led to very high strengths, with yield strengths close to 1400 MPa, but very limited ductility. These results indicate that for tube fabrication, high temperature anneals will likely be required after each cold pilgering step to avoid detrimental hardening of the 106ZY alloy. Finally, atom probe tomography (APT) analysis of alloy 106ZY, and a similar alloy without Zr addition (106Y) was conducted to determine the impact of Zr on the ODS FeCrAl alloy microstruc- ture.The presence of a large number of (Y,Al,O) nanoclusters, ~2 to 10nm in diameter was observed for both alloys, and larger Zr carbonitrides were also detected for alloy 106ZY.The beneficial effect of Zr is related to the entrapment of impurities such as C and N, but Zr addition does not seem to affect the formation of (Y,Al)-rich nano oxides. Large Fe-10Cr-6Al- 0.3Zr ODS rods with excellent steam oxidation resistance, mechanical strength and ductility were fabricated at ORNL to be used for production of accident tolerant fuel cladding.