摘要
针对K418合金增压器涡轮叶片的热裂问题进行了研究。采用光学显微镜和扫描电镜分析了Al、Ti含量对K418合金显微组织的影响。利用Thermo-Calc热力学软件计算了K418合金中可能析出的平衡相,并分析了Al、Ti含量变化对平衡相的影响。结果表明:Al、Ti含量增加后,K418合金的显微组织发生了明显变化,γ′的尺寸增大且形状多样化,(γ+γ′)共晶增多,导致裂纹优先产生和扩展的部位增多;热裂为枝晶组织断裂,热裂纹在枝晶间产生和扩展;Al、Ti含量的增加均提高了γ′的析出温度和析出量,Al的影响尤为明显;Al、Ti含量增加后,均扩大了合金的有效结晶温度范围,导致涡轮叶片产生热裂。
The hot tearing of K418 alloy turbocharger turbine blades was investigated.The effects of aluminum and titanium content on the microstructure of K418 alloy were analyzed by optical microscope and scanning electronic microscope（SEM）.The probable equilibrium phases in K418 alloy were calculated and the effects of changing of aluminum and titanium content on the equilibrium phases were studied by Thermo-Calc software.The results show that the microstructure of K418 alloy changes obviously with the aluminum and titanium content increasing.The size of γ＇ and the amount of（γ＋γ＇） eutectic increase,resulting in more prior forming and propagating areas of the hot tearing.The hot tearing is caused by the fracture of dendrites structures,forming and propagating along the interdendrites.The precipitation temperature and mass fraction of γ＇ rise with aluminum and titanium content increasing,and especially aluminum has a more important effect.The effective crystallization temperature interval is broadened with aluminum and titanium content increasing,which leads to the hot tearing of the turbine blades.
出处
《稀有金属材料与工程》
SCIE
EI
CAS
CSCD
北大核心
2012年第11期1935-1939,共5页
Rare Metal Materials and Engineering
