温度与加载波形对Ni_3Al(B)疲劳-蠕变裂纹扩展行为的影响

EFFECTS OF TEMPERATURE AND LOADING WAVEFORM ON CREEP-FATIGUE CRACK GROWTH OF Ni_3Al(B)

在不同加载波形及温度下研究了NiaAl（B）的疲劳－蠕变裂纹扩展行为．结果表明。加载波形对高温疲劳－蠕变裂纹扩展速率及断裂行为有强烈影响，拉伸保持时间的叠加明显增加合金高温下的蠕变裂纹扩展速率．与高温合金相比，Ni3Al（B）在600和800℃下的裂纹尖端氧脆及疲劳－蠕变交互作用更为明显，裂纹扩展速率随温度发生明显变化．B在高温下对Ni3Al（B）的韧化作用与温度和加载波形有关．

The study of fatigue-creep crack growth of Ni3Al(B) alloy under different loading waveforms in air at elevated temperatures was carried out. It was found that there are strong effects of loadingwaveform on fatigue crack growth rate(FCGR). The applied tensile hold accelerated the FCGR at elevatedtemperature. As compajred with superalloys, the oxidation-induced embrittlement at the crack tip andfatigue-creep interaction at 600 and 800℃ are more significant. The crack growth rate changes stronglywith increasing temperature. The effects of boron on toughness and fatigue--creep crack growth of Ni3Al(B)at elevated temperatures were related to temperature and loading waveform.