低膨胀高温合金膨胀系数的物理表征

测定了低膨胀高温合金的膨胀系数和饱和磁化强度随温度变化的曲线，并将实验结果与普通的高温合金及低膨胀合金进行了比较。提高低膨胀高温合金的低膨胀特性及使用的最高温度，应通过各种手段使合金具有一定的饱和磁化强度，但并非越高越好，同时应尽量减缓其随温度升高而降低的速度，并提高合金的居里点温度。导致合金低膨胀的原因之一是在正常的热膨胀过程中叠加了磁性行为的变化，从而引起负膨胀

Physical denotation of thermal expansion coefficient of low thermal expansion superalloys

The relationship between mean linear expansion coefficient and saturation magnetization of low thermal expansion superalloy with temperature was studied.Comparing the data gained in this experiment with those of conventional superalloy and low expansion alloy showed that in the proper scope of saturation magnetization the best result of the property of low expansion for the low expansion superalloy could be gained and such low expansion feature could be retained to the reasonable higher temperature;on the contrary,too high saturation magnetization was detrimental. We should pay much attention to raise Curie temperature and decrease the rate of lowering of the saturation magnetization.The results also showed that the one of the reasons of low expansion was that the change of the magnetic behavior overlapped on the normal expansion process;this behavior induced the negative expansion of superalloy.This investigation opened a new prospect and made a good foundation to the development of low expansion superalloy.