Ni-Al二元合金γ相高温点阵常数及热膨胀系数的试验与计算研究

Experimental and Computational Studies of Lattice Parameter and Thermal Expansion Coefficient of γ Phase in Ni-Al Alloy

采用高温X射线衍射及热膨胀法,测定了较宽温度范围内γ单相及γ+γ'两相Ni-Al合金中γ相的点阵常数及热膨胀系数。将试验结果与文献中的计算结果进行比较,发现在600~900℃范围内γ相点阵常数与热膨胀系数的试验值均小于Wang等的计算结果;相较于γ单相Ni-Al合金,γ+γ'两相合金中γ相点阵常数的试验值随温度的变化趋势与计算结果更吻合。分析认为,这是由于Wang等的点阵常数模型未考虑两相状态时共格应力对γ相点阵常数的影响。

Lattice parameter and coefficient of thermal expansion(CTE)of γ phase in γ single-phase and γ+γ'two-phase Ni-Al alloys over a wide temperature range were measured by hightemperature X-ray diffraction and thermal dilation method.Comparing the experimental results with the calculated results in literature,it was found that the measured values of lattice parameter and CTE of γ phase in the temperature range of 600 to 900℃ were smaller than those calculated by Wang et al.The trend of variation of lattice parameter of γ phase with temperature in γ+γ'two-phase alloy obtained from experiment was more consistent with the calculated results than that in γ single-phase Ni-Al alloy.It resulted from that the effect of coherent stress on the lattice parameter of γphase in two-phase state was not considered in Wang et al’s lattice parameter model.