(1. 重慶儀表材料研究所 國家儀表功能材料工程技術(shù)研究中心，重慶 400700；
2. 北京科技大學(xué) 材料科學(xué)與工程學(xué)院，北京 100083)
摘 要: 利用DSC-TG試驗方法，對新型國產(chǎn)耐蝕合金3YC51在室溫~1 600 ℃溫度范圍內(nèi)的相態(tài)變化和1 300 ℃恒溫氧化行為進行研究。DSC曲線結(jié)果顯示，升溫段在673、809與911 ℃處存在3個扁平的吸熱峰，經(jīng)SEM和EPMA分析，3個吸收峰分別對應(yīng)于γ ′、γ ″和d 相；在720～980 ℃溫區(qū)內(nèi)存在相的析出和轉(zhuǎn)變反應(yīng)，反應(yīng)終止于980 ℃；合金在1 224.8 ℃出現(xiàn)初熔，在1 354.6 ℃出現(xiàn)陡降最大放熱峰，分析表明存在金屬碳氮化物(Nb3CN與Ti3C)的共晶析出；在降溫過程中，1 158.5 ℃出現(xiàn)一個較強的放熱峰，對應(yīng)析出的共晶Laves相；SEM和EPMA觀察分析發(fā)現(xiàn)，合金中始終存在高熔點金屬碳氮化物。合金在空氣中氧化起始溫度為1 047 ℃，由dTG曲線(d(∆m)/dt)判斷其起始氧化速率較快，在1 153 ℃時達到最大值0.04 mg/min，3YC51合金在常壓和1 300 ℃恒溫氧化質(zhì)量增量符合拋物線動力學(xué)規(guī)律；高溫擴散導(dǎo)致氧化層有高溫碳氮化合物和呈島狀結(jié)構(gòu)的空洞出現(xiàn)。
關(guān)鍵字: 鎳基耐蝕合金；相態(tài)轉(zhuǎn)變；高溫氧化；動力學(xué)
（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
