通过扫描电子显微镜研究了保温时间和缺口半径对DZ951合金热疲劳性能的影响.结果表明,在相同上限温度下,随着保温时间的延长,合金裂纹萌生次数增加,热疲劳抗力提高.铸态合金热疲劳裂纹在碳化物处萌生.热处理合金通过氧化萌生裂纹.裂纹萌生后,主要通过氧化产生孔洞并通过孔洞相互连接使裂纹扩展.热疲劳裂纹沿着与枝晶生长方向呈45°角扩展.热处理合金具有优异的热疲劳性能.随着缺口半径的增加,应力集中减小,合金热疲劳性能提高.
lnfluence of holding time and notched radius of thermal fatigue specimen on thermal fatigue property of D2951 alloy was investigated by scanning electron microscopy. The results show that the numbers of thermal cycle for crack initiation and resistance of thermal fatigue crack growth increase with the rise of holding time at the same upper temperature. The thermal fatigue crack is initiated at carbide in the as-cast D2951 alloy and the thermal fatigue crack in heat treated alloy is mainly initiated by oxidized cavities. The connection of oxidized cavities is responsible for thermal fatigue crack propagation. The thermal fatigue crack propagates in direction at an angle of 45° to the orientation of crystal growth. Heat treated alloy exhibits excellent thermal fatigue property. The thermal fatigue property of D2951 alloy improves with the increase of notched radius of the specimens.
参考文献
| [1] | Sima C T.Superalloys Ⅱ[M].New York:John Wiley and Sons,Inc,1987:3-15. |
| [2] | Matthew J;Donachie J.Superalloy[M].Ohio:American Society for Metals,1984:3-12. |
| [3] | Woodfood D A;Mowbray D F .Effect of material characteristic and test variable on thermal fatigue of cast superalloya[J].Materials Science and Engineering,1974,16:5-43. |
| [4] | Frankli A W;Heslop J;Smith R A .Some metallurgical factors influencing the thermal fatigue resistance of wrought Ni-Cr base high-temperature alloys[J].Journal of the Institute of Metals,1964,92:313-322. |
| [5] | 夏鹏成,于金江,孙晓峰,管恒荣,胡壮麒.DZ951合金的热疲劳性能[J].稀有金属材料与工程,2008(01):50-53. |
| [6] | 李友林,袁超,郭建亭.铸造镍基高温合金K445的热疲劳行为[J].金属学报,2006(10):1056-1060. |
| [7] | Glenny E;Taylor T A J .A study of thermal fatigue behavior of metals:the effect of test conditions on nickel-base high-temperatures alloy[J].Journal of the Institute of Metals,1959,88:449-461. |
| [8] | XIA Peng-cheng,禹文芳,YU Jin-jiang,李武,SUN Xiao-feng,管恒荣,HU Zhuang-qi.标准热处理对DZ951合金组织和性能的影响[J].材料热处理学报,2008(04):96-99. |
- 下载量()
- 访问量()
- 您的评分：
-
10%
-
20%
-
30%
-
40%
-
50%