title: Solid State Reaction Mechanism and Microstructure Evolution of Ni-Al Powders during High Energy Ball Milling Revisited by TEM.
abstract: Microstructure evolution during the formation of B2-NiAl by high energy ball milling of equiatomic elemental mixtures was studied by X-ray diffractometer, scanning electron microscopy, and transmission electron microscopy (TEM). The crystallite size, lattice defects and ordering of the B2-NiAl were monitored via TEM as function of milling time. The diffusion reaction, Ni+Al→NiAl3 or/and Ni2Al3, occurred during high energy ball milling, and to a certain extent offered the stored energy for the explosive exothermic reaction, Ni+Al→B2-NiAl. The fine microstructure of newly formed B2-NiAl after 5 h milling involved high density defects, e.g. antiphase boundary, long range ordering domains, vacancies, and dislocations.
authors.affiliation: 1School of Materials Science and Engineering,Harbin Institute of Technology,Harbin 150001,People's Republic of China.
authors.forename: Guohua
authors.initials: G
authors.lastname: Fan
authors.affiliation: 1School of Materials Science and Engineering,Harbin Institute of Technology,Harbin 150001,People's Republic of China.
authors.forename: Lin
authors.initials: L
authors.lastname: Geng
authors.affiliation: 2School of Materials Science and Engineering,Harbin University of Science and Technology,Harbin 150040,People's Republic of China.
authors.forename: Yicheng
authors.initials: Y
authors.lastname: Feng
authors.affiliation: 1School of Materials Science and Engineering,Harbin Institute of Technology,Harbin 150001,People's Republic of China.
authors.forename: Xiping
authors.initials: X
authors.lastname: Cui
authors.affiliation: 1School of Materials Science and Engineering,Harbin Institute of Technology,Harbin 150001,People's Republic of China.
authors.forename: Xudong
authors.initials: X
authors.lastname: Yan
keywords: exothermic reaction; mechanical alloying; nickel aluminide; transmission electron microscopy