Microstructure evolution of nanostructured Ni3Al during annealing
(1. Key Laboratory of Ministry of Education for High Temperature Materials and Tests,
School of Materials Science and Engineering, Shanghai Jiao Tong University, Shanghai 200030, China;
2. Baosteel Technology Centre, Baoshan Iron & Steel Co. Ltd, Shanghai 201900, China)
School of Materials Science and Engineering, Shanghai Jiao Tong University, Shanghai 200030, China;
2. Baosteel Technology Centre, Baoshan Iron & Steel Co. Ltd, Shanghai 201900, China)
Abstract: A nanocrystalline layer was produced on the surface of Ni3Al intermetallic by means of surface mechanical attrition treatment. The surface nanocrystallites were annealed at 250−750 ℃ for 30 min. Microstructure evolution of nanocrystallites during annealing was studied by X-ray diffraction (XRD) and transmission electronic microscope (TEM). The experimental results show that long-rang order recovers rapidly when annealing temperature is below 250 ℃ and changes slowly at 350−550 ℃, and then it increases rapidly at 750 ℃. The grain size of nanocrystallites of Ni3Al keeps stable and crystal defects recover when they are annealed below 550 ℃. The grains grow normally in low temperature annealing and abnormal growth occurs at 750 ℃.
Key words: Ni3Al; intermetallic compound; nanocrystallite