Ti对Cr35Ni5导卫板热疲劳和抗氧化性能的影响

Effect by Ti on Thermal Fatigue Resistance and Oxidation Resistance of Cr35Ni5 Guide Plate

探究了Ti含量对Cr35Ni5导卫板耐热疲劳性和抗氧化性的影响。结果表明,随着温度升高,不同Ti含量试样表面出现裂纹时经过的冷热循环次数均减少。含0.9%Ti试样在600℃热疲劳试验中,经10次冷热循环产生裂纹,相比于不含Ti试样的耐热疲劳性能提高一倍;含0.9%Ti试样在900℃氧化试验中,经50 h氧化增重1.6 mg,相比于不含Ti试样的氧化增重减少0.7 mg,同时氧化膜变得更加致密。在Cr35Ni5材质中加入适量Ti,Ti与C形成TiC,TiC形成温度较高,在熔体中优先形成,作为碳化物异质形核基底,提高了形核率,从而细化初生碳化物,改善组织,提高了Cr35Ni5导卫板的耐热疲劳性和抗氧化性。

Investigated is the effect by Ti content on ther mal fatigue resistance and oxidation resistance of the Cr35Ni5 guide plate.As a result it is identified that along with increase of the temperature,the number of the cold and hot circulation cycles as experienced by the specimens with different Ti contents are reduced,when cracks occurring on their surfaces.During the thermal fatigue test to the 0.9% Ti specimen as made at 600℃,cracks occurred after 10 hot and cold cycles.Compared with the specimen without Ti,the thermal fatigue resistance is doubled;and during oxidation test to the 0.9%Ti specimen as made at 900℃,after 50 hours of oxidation,the specimen weights 1.6 mg more via oxidation.Compared with the specimen without Ti,the post-oxidation weight is lessened by 0.7 mg,and the oxide film becomes denser.Adding an appropriate amount of Ti to the Cr35Ni5 material,Ti and C form TiC,and TiC is formed at a higher temperature,and is preferentially fonned in the melt.It serves as a heterogeneous carbide nucleation base,and thus increases the nucleation rate,thereby refining the primary carbides,and then improving the structure,so as to eventually improve the heat fatigue resistance and oxidation resistance of the guide plate.