钢中夹杂物与奥氏体基体热膨胀系数差异导致的热应力和应变能研究

考虑基体的屈服，对钢中的球形夹杂物和奥氏体基体之间因热膨胀系数差在降温过程中产生的热应力，应变和应变能作了理论研究。大的过冷度和热膨胀系数差异是产生大的热应力、应变和高应变能的主要原因，在现实条件下，夹杂物的Young’s模量和Poisson比的变化对上述参量产生的影响不大，主要计算了几种典型的夹杂物和奥氏体产生的热应力、应变和应变能。结果显示，即便对于极限状态的“刚性”夹杂物，热应力形成的应变能也比相变化学驱动力小1—2个数量级。

STUDY OF THERMAL STRESS AND STRAIN ENERGY IN γ-Fe MATRIX AROUND INCLUSION CAUSED BY THERMAL COEFFICIENT DIFFERENCE

The thermal stresses, strains and strain energy in 7-Fe matrix around a spherical inclusion caused by the difference of their thermal expansion coefficients during cooling were studied theoretically incorporating the matrix yielding. High undercooling and large thermal coefficient difference are the main factors resulting in large thermal stresses, strains and high strain energy around inclusions while the variations in Young's modulus and Poisson's ratio of inclusions in real situations seem to play a little role in changing values of the above parameters. Some specific inclusions including suppositional rigid ones were introduced into calculations and different values of strain energy were worked out and a comparison with the driving force for ferrite nucleation demonstrates that thermal strain energy is less than the driving force by 1-2 order of magnitude.