冷轧变形对Inconel 718合金δ相析出动力学的影响

EFFECT OF COLD ROLLING ON THE KINETICS OF δ PHASE PRECIPITATION IN INCONEL 718

采用X射线衍射测定了冷轧Inconel718合金在不同加热条件下的δ相含量，研究了冷轧变形对δ相析出动力学的影响．结果表明，δ相析出的质量分数与时间的关系符合Avrami方程，在加热温度为960℃时，冷轧变形量对时间指数（n）和δ相析出速率（α）的影响不大；低于910℃，随冷轧变形量的增加和加热温度的提高，n值减小而α值增加．δ相的析出速率与加热温度的关系符合Arrhenius方程，随冷轧变形量增加，δ相析出激活能降低，冷轧变形促进γ＂→δ转变，给出了冷轧Inconel718合金δ相等温析出动力学曲线（PTT），随冷轧变形量增加，C曲线向左移动．

The mass percentages of δ phase in Inconel 718 cold rolled to different reductionsand then treated at different temperatures for different times were measured by X-ray diffraction,and the effect of cold rolling on the kinetics of δ phase precipitation was investigated. Therelationship between the mass percentage of δ phase and annealing time follows the Avramiequation. At 960℃, cold rolling has a little effect on the time exponent (n) and the rate constantof δ phase (α). Below 910 ℃, as cold rolling reduction and annealing temperature increases, theValue of n decreases, whereas the value of or increases. The relationship between the rate constantof δ phase and temperature follows Arrhenius equation. As cold roiling reduction increases,the apparent activation energy of δ precipitation decreases. Cold rolling promotes the γ' → δtransformation. According to the kinetics of δ precipitation, the precipitation-temperature-time(PTT) curves of δphase were given.It has been found that the C curve shifts left as cold rolling reduction increases.