在25℃和-40℃环境下的三种航空材料的裂纹扩展品质研究

Study on Crack Growth Behaviors of Three Kinds of Aeronautical Materials at 25℃ and -40℃

为了探讨室温和低温环境下的航空金属材料的裂纹扩展特性,进行了-40℃和25℃两种温度环境下的LY12CZ,LC4CS和30CrMnSiNi2A3种材料的a-N和da/dN-△K曲线的对比试验研究。从试验结果比较得出,这3种材料在-40℃的a-N曲线和da/dN-△K曲线全部高于25℃下的a-N曲线和da/dN-△K曲线,说明这3种材料在-40℃环境下的裂纹扩展速率要比在25℃(常温)下的裂纹扩展速率要低,即同样材料在同一载荷谱作用下,低温环境下的裂纹扩展寿命要高于常温环境下的裂纹扩展寿命。

To study the crack growth behaviors of areonautical materials at low temperature and room tempera ture, the α-N curves and dα/dN -△K curves of LY12CZ, LC4CS aluminium alloys and 30CrMnSiNi2A steel are tested at -40℃ and 25℃ separately. Through the results, it can be found that the α-N curves and the dα/ dN-△K curves of these materials at -40℃ are both higher than those of at 25℃. All the results show that the crack growth rates of the materials at at -40℃ are lower than those at 25℃, namely at the same condi tion, the crack growth lives the materails at low invironmenl are higher than those al room invironmenl.