Compressive and tensile pre-strains at room temperature were induced in the second generation single crystal superalloy CMSX-4 fully heat treated.Both compressive and tensile pre-strain generated shear bands in the si...Compressive and tensile pre-strains at room temperature were induced in the second generation single crystal superalloy CMSX-4 fully heat treated.Both compressive and tensile pre-strain generated shear bands in the single crystal CMSX-4.Thermal exposure for 10 h at 950 ℃ on the pre-strained single crystal CMSX-4 developed preferential coarsening of γ＇ particles along the shear bands.γ＇ particles on the shear band gradually invaded γ channel.Finally,the γ channels along the shear band disappeared.TCP-like particles appeared at the expense of γ channel disappearance.However,thermal exposure for 10 h of the normal single crystal CMSX-4 did not develop TCP precipitation or preferential coarsening of γ＇ particles.Thermal exposure for 100 h of pre-strained CMSX-4 developed preferential coarsening of γ＇ and TCP phase particles along the shear bands as well as coarsening of γ＇ particles in the matrix.展开更多
采用含Si的BNi-5非晶箔片作为中间层合金对CMSX-4镍基单晶合金棒在放电等离子体烧结炉中进行TLP连接,采用SEM观测了TLP接头在不组织形貌特征,借助于EDS分析了TLP接头界面处的物相组成及其对接头力学性能的影响。采用常温和高温拉伸试验...采用含Si的BNi-5非晶箔片作为中间层合金对CMSX-4镍基单晶合金棒在放电等离子体烧结炉中进行TLP连接,采用SEM观测了TLP接头在不组织形貌特征,借助于EDS分析了TLP接头界面处的物相组成及其对接头力学性能的影响。采用常温和高温拉伸试验验证了不同焊接工艺条件对TLP接头性能的影响。结果表明,在1 200℃/5 k N/20 min工艺参数下可得到满意的TLP接头,此时组织分布较为均匀,常温抗拉强度达到了母材的95%,760℃高温抗拉强度达到母材的99%。展开更多
Prolonged tension tcsts were caTried out by comblning elevated temperatures with declined stresses over thc range of 760-1050° C and 780-115MPa. The effects of temperature and applied stress on rupture life, and ...Prolonged tension tcsts were caTried out by comblning elevated temperatures with declined stresses over thc range of 760-1050° C and 780-115MPa. The effects of temperature and applied stress on rupture life, and the relations of temperuture, applied stress and mpture life to characteristic dimensions of coherent phases (γ matrix channel width and mpcd γ precipitate thickness), and to the elongation as well as to the cross sectional area reduction of thc tested specimens were investigated. Under all testing conditions, longittLdinal coalescence of seveml adjacent armys of γ precipitates could occur to dtherent extents along the direction of the applied stress axis in addition to their normal directional coarsening. The extent of γ Longitudinal coalescence became increased and its morphology tended to be irmpular with the increase of temperuture although the applied stresses were relatively lower.展开更多
Hot corrosion is a serious problem in aircraft, marine, industrial and land-base gas turbines. To obviate these problems, superalloy superfer 800H (Midhani grade) is one of the prominent materials for the high tempera...Hot corrosion is a serious problem in aircraft, marine, industrial and land-base gas turbines. To obviate these problems, superalloy superfer 800H (Midhani grade) is one of the prominent materials for the high temperature applications. The present work investigates hot corrosion behaviour of superfer 800H exposed to two different molten salt environments Na2SO4 + 60% V2O5 and Na2SO4 + 5% V2O5 + 5% NaCl respectively, at 900oC under cyclic conditions. The weight change measurements made on during the experiments are used to determine the kinetics of hot corrosion. It is observed that the formation of scale rich in Cr2O3, NiO and spinel NiCr2O4 has contributed for the better hot corrosion resistance of superfer 800H. Inspection for 10, 20, 35 and 50 cycles reveals that after 10 cycles Crack has been initiated in the scale and it is clearly visible in the presence of NaCl salt. On subsequent cycles, crack propagates perpendicular to surface and as it encounters inclusions.展开更多
文摘Compressive and tensile pre-strains at room temperature were induced in the second generation single crystal superalloy CMSX-4 fully heat treated.Both compressive and tensile pre-strain generated shear bands in the single crystal CMSX-4.Thermal exposure for 10 h at 950 ℃ on the pre-strained single crystal CMSX-4 developed preferential coarsening of γ＇ particles along the shear bands.γ＇ particles on the shear band gradually invaded γ channel.Finally,the γ channels along the shear band disappeared.TCP-like particles appeared at the expense of γ channel disappearance.However,thermal exposure for 10 h of the normal single crystal CMSX-4 did not develop TCP precipitation or preferential coarsening of γ＇ particles.Thermal exposure for 100 h of pre-strained CMSX-4 developed preferential coarsening of γ＇ and TCP phase particles along the shear bands as well as coarsening of γ＇ particles in the matrix.
文摘采用含Si的BNi-5非晶箔片作为中间层合金对CMSX-4镍基单晶合金棒在放电等离子体烧结炉中进行TLP连接,采用SEM观测了TLP接头在不组织形貌特征,借助于EDS分析了TLP接头界面处的物相组成及其对接头力学性能的影响。采用常温和高温拉伸试验验证了不同焊接工艺条件对TLP接头性能的影响。结果表明,在1 200℃/5 k N/20 min工艺参数下可得到满意的TLP接头,此时组织分布较为均匀,常温抗拉强度达到了母材的95%,760℃高温抗拉强度达到母材的99%。
文摘Prolonged tension tcsts were caTried out by comblning elevated temperatures with declined stresses over thc range of 760-1050° C and 780-115MPa. The effects of temperature and applied stress on rupture life, and the relations of temperuture, applied stress and mpture life to characteristic dimensions of coherent phases (γ matrix channel width and mpcd γ precipitate thickness), and to the elongation as well as to the cross sectional area reduction of thc tested specimens were investigated. Under all testing conditions, longittLdinal coalescence of seveml adjacent armys of γ precipitates could occur to dtherent extents along the direction of the applied stress axis in addition to their normal directional coarsening. The extent of γ Longitudinal coalescence became increased and its morphology tended to be irmpular with the increase of temperuture although the applied stresses were relatively lower.
文摘Hot corrosion is a serious problem in aircraft, marine, industrial and land-base gas turbines. To obviate these problems, superalloy superfer 800H (Midhani grade) is one of the prominent materials for the high temperature applications. The present work investigates hot corrosion behaviour of superfer 800H exposed to two different molten salt environments Na2SO4 + 60% V2O5 and Na2SO4 + 5% V2O5 + 5% NaCl respectively, at 900oC under cyclic conditions. The weight change measurements made on during the experiments are used to determine the kinetics of hot corrosion. It is observed that the formation of scale rich in Cr2O3, NiO and spinel NiCr2O4 has contributed for the better hot corrosion resistance of superfer 800H. Inspection for 10, 20, 35 and 50 cycles reveals that after 10 cycles Crack has been initiated in the scale and it is clearly visible in the presence of NaCl salt. On subsequent cycles, crack propagates perpendicular to surface and as it encounters inclusions.
文摘CMSX-4是目前世界上应用最广泛的第二代镍基单晶高温合金,在CMSX-4中添加微量的镧(La),铈(Ce)等稀土元素可以显著提高合金的抗氧化性和耐腐蚀性。本文建立了湿法消解-电感耦合等离子体质谱法(ICP-MS)同时测定CMSX-4镍基高温合金中La, Ce元素含量的方法。样品经王水-HF常压加热溶解,利用HClO4冒烟消除F-的干扰,优化了溶样用酸的量和消解条件。在优化条件下,方法的检出限为La 0.23μg/g, Ce 0.85μg/g,加标回收率为95.0%~98.9%,相对标准偏差(RSD)为1.3%~3.9%,能够用于对CMSX-4镍基高温合金中微量La和Ce元素的准确、快速测定。
基金Ministry of Major Science&Technology of Shanghai(19DZ1100703)National Natural Science Foundation of China(51472263)+1 种基金Shanghai Institute of Ceramics,Chinese Academy of Sciences Launched the Fund in Advance(Y82ZC8180G)Key Laboratory of Space Manufacturing,Chinese Academy of Sciences(SMT-2019-004)。
