Research On The Room Temperature Mechanicalproperties And δ Phase Precipitation Of Cold Rolled GH4169 Alloy

GH4169 alloy is a nickel-based superalloy. It is widly used in the fileds of aerospcace, energy because of its high strength, good plasticity and fatigue properties. After cold rolling and solution, the mechanical properties of GH4169 alloy were tested at room temperature. The effect of δ phase on the mechanical properties was investigated. Then, the experiments of δ phase precipitation with different rolling reduction were carried out at different aging treatments. The fraction, distribution and morphology of δ phase was observed. At last, the kinetic model of GH4169 alloy based on the different cold rolling reduction was established.Through the tensile tests of GH4169, the mechanical properties after cold rolling and solution were acquired. The reason of the strength improvement was analysed. The results show that the strengths of the specimens after cold rolling increase with the increase of cold rolling reduction. After the solution, the strengths are further improved. The elongation of these two states decrease all the time; δ phase precipitation increased with the increase of the cold rolling deformation. Besides, the fraction of δ phase increase from 3.45 wt.% to 8.93 wt. %, the moprphology changes from neddle or short rod shape to particle one, and its distribution change from grain boundary to transgranular. The precipitation of δ phase is the main reason for the strength improvement.Through the different aging treatments, the precipitation law of δ phase based on the cold rolling reduction of 0%、30%、50% was obstained. The results show that the cold rolling deformation promotes the precipitation of δ phase. It shortens the initial precipitation time. Except that, the partical δ phase more easily precipitates with the increase of cold rolling reduction.At last, the kinetic model of GH4169 alloy based on the different cold rolling reduction was established. The results show that the precipitations of δ phase under different rolling reduction conditions still meet the Avrami equation. In addition, the time index decrease with the increase of cold rolling reduction, while the precipitation rate index increase instead.