Study On Precipitation Process Of Ni)(75)Al₁₄ Mo₁₁ Alloy Under The Strain Energy Field

Nickel-based alloy is widely used in the aviation industry because of its good high-temperature creep degeneration resistance, fatigue resistance, oxidation resistance, corrosion resistance, etc. Ni3X structure is the main strengthening phase in nickel-based alloy, its morphology directly affects the mechanical properties of nickel-based alloy. In the precipitation process, elastic energy and atomic interaction energy play an important role in the morphology, arrangement and the precipitation degree of Ni3X precipitation phase. Meanwhile, the interface structure of nickel-based alloy which appears with precipitation influences the properties of alloy.The Ni₇₅Al₁₄Mo₁₁ alloy precipitation process is visually described through computer simulation by using MATLAB language program based on the microscopic phase-field dynamics model. In this paper we researched the elastic energy and atomic interaction energy influence on the nickel-based alloy precipitation process and the changing rule of the interface during the precipitation process.When elastic energy come into existence,the morphology of precipitation phase changed from elliptic to blocks,arrangement of precipitation changed from irregular random arrangement to rule arrangement along the elastic soft direction with certain direction; the elastic energy made inhibitory action to the short range ordered phase DO22, and the influence of coarsening process was greater than the effect of precipitation process.The elastic energy influence on ordering and clustering was not simple inhibition or promotion with the increase of elastic energy, but it was related to the scope of elastic energy. Because the two average order parameter curves overlapped together when the elastic energy constant were 0 and 500, which indicated that the influence of elastic energy constant B=0 on the ordering and clustering of the precipitation phase was the same as that of elastic energy constant B=500.The increase of the first and third Ni-Mo atomic interaction energy enhanced the ordering and clustering of the early precipitation phase, and the change restrained the later reverse precipitation of Ni atom; the influence of increase of the second and fourth atomic interaction energy on the precipitation process was opposite to that of the first and third atomic interaction energy. The increase of the first and third atomic interaction energy of Ni-Al enhanced the whole precipitation process of Ni₇₅Al₁₄Mo₁₁ alloy, and the increase of second and fourth atomic interaction energy restrained it.As the first/the third Al-Mo atomic interaction energy increased the hole process of precipitation was inhibited, As the first/the third Al-Mo atomic interaction energy increased the ordering and clustering of precipitation phase were promoted, reverse exhalation of nickel atomic was inhibited. The influence of the outermost Ni-Mo, Ni-Al and Al-Mo atomic interaction energy on ordering and clustering was the maximum.The interfaces were composed by the (001)γ′and (001)γ′in Ni₇₅Al₁₄Mo₁₁ alloy precipitation, the atom number of the interface increased continuously and the nickel atom structure of reverse precipitation changed from ordering to disordering with the processing of precipitation. In this process, the interface was not moved but grew wider because of the continuous exhalation nickel atomic in interface.