高温合金晶粒尺寸和晶界沉淀对冲击韧性的影响

The Effect of Grain Size and Grain Boundary Precipitation on ImpactToughness of Superalloy

用晶界萃取碳复型技术研究了三种不同强化程度高温合金晶界沉淀随工艺因素和成分的变化规律,探讨了晶粒尺寸、晶界沉淀与冲击韧性的关系。在晶内、晶界沉淀等因素变化较小的前提下,随晶粒几何尺寸增大,合金的冲击韧性升高;而晶内沉淀和晶粒尺寸等因素基本相同时,随晶界沉淀(包括所研究合金中的M23C6、δ相和M3B2相)尺寸和面分布密度的增大、形貌的脆性化(如薄膜状、枝晶状),冲击韧性大幅度下降。

The law of variation of grain boundary precipitation with the changing of processing factors and chemical compositions of three strengthened superallys was studied with the application of extracted carbon replica technique on grain surfaces. The relationship between grain size, grain boundary precipitation and impact toughness was discussed. The impact toughness of the superalloy increased with the increase of the grain size on the premise of less changing of intragranular precipitation, grain boundary precipitation, etc. When intragranular precipitation and grain sizes are basically the same, the impact toughness decreased drastically with the increase of the size of grain boundary precipitation (including M23C6 phase, delta phase and M3B2 phase in the tested superalloy) and its distribution density in area and morphology becoming fragiler (such as filmy and dendritic).