(1. 重庆仪表材料研究所 国家仪表功能材料工程技术研究中心，重庆 400700；
2. 北京科技大学 材料科学与工程学院，北京 100083)
摘 要: 利用DSC-TG试验方法，对新型国产耐蚀合金3YC51在室温~1 600 ℃温度范围内的相态变化和1 300 ℃恒温氧化行为进行研究。DSC曲线结果显示，升温段在673、809与911 ℃处存在3个扁平的吸热峰，经SEM和EPMA分析，3个吸收峰分别对应于γ ′、γ ″和d 相；在720～980 ℃温区内存在相的析出和转变反应，反应终止于980 ℃；合金在1 224.8 ℃出现初熔，在1 354.6 ℃出现陡降最大放热峰，分析表明存在金属碳氮化物(Nb3CN与Ti3C)的共晶析出；在降温过程中，1 158.5 ℃出现一个较强的放热峰，对应析出的共晶Laves相；SEM和EPMA观察分析发现，合金中始终存在高熔点金属碳氮化物。合金在空气中氧化起始温度为1 047 ℃，由dTG曲线(d(∆m)/dt)判断其起始氧化速率较快，在1 153 ℃时达到最大值0.04 mg/min，3YC51合金在常压和1 300 ℃恒温氧化质量增量符合抛物线动力学规律；高温扩散导致氧化层有高温碳氮化合物和呈岛状结构的空洞出现。
关键字: 镍基耐蚀合金；相态转变；高温氧化；动力学
（1. National Instrument Engineering Technology Research Center for Functional Materials,
Chongqing Instrument Materials Research Institute, Chongqing 400700, China;
2. School of Materials Science and Engineering, University of Science and Technology Beijing, Beijing 100083, China）
Abstract:Both the phase transition from room temperature to 1 600 ℃ and the isothermal oxidation behavior at 1 300 ℃ of the new-type corrosion resistance alloy (CRA) 3YC51 were studied by DSC-TG techniques. The DSC results show that three flat endothermic peaks are detected at 673, 809 and 911 ℃ corresponding to the phases γ ′, γ ″ and δ by the analysis of SEM and EPMA, the precipitations end at 980 ℃, the phenomena of phases precipitation and transition reaction are evident in the temperature range of 720−980 ℃. The incipient melting temperature of the alloy appears at 1 224.8 ℃. At 1 354.6 ℃ there is a strong sharp exothermal peak, indicating that there exists an eutectic reaction for metal carbide and carbo-nitride eutectics (Ti3C and Nb3CN). At the decreased temperature a prominent exothermic peak appears, corresponding to the Laves phase at 1 158.5 ℃. The high melting-point metal carbo-nitrides are always found in the alloy matrix on the basis of the observation by EPMA and SEM. In the isothermal oxidation in the air, the samples 3YC51 start to be oxidized at 1 047 ℃. From the dTG curve it is seen that the oxidation rate is higher at the beginning in this case (maximum oxidation rate of 0.04 mg/min at 1 153 ℃) followed by another step with a lower oxidation rate. 3YC51 alloy exhibits parabolic, diffusion-controlled oxidation rate dependence in the air at atmospheric pressure and 1 300 ℃. High-temperature diffusion induces the oxide scales including the high-temperature carbo-nitrides and island- like cavities.
Key words: nickel-based corrosion resistance alloy; phase transition; high-temperature oxidation; dynamics
