DZ125定向凝固涡轮叶片合金研究

ＤＺ１２５定向凝固高温合金是为新航空发动机研制的涡轮叶片材料，。它具有高的中，高温强度和延性，特别是具有良好的可铸性和小的薄壁效应，可铸成内腔十分复杂的薄壁空心叶片。     

DirectionaHy Solidified High-strength Superalloy DZ22

Alloy DZ22 possesses rather high intermediateand elevated temperature mechanical propertiescomparable with the advanced commercial DS al-loy PWA1422.The alloy composition is based onPWA1422 alloy,only the content ranges of Hf,Cand Zr are changed for systematic study.The pres-ent melting technology for master alloy ingot andDS process parameters for components are suitablefor this alloy.The alloy revert which has     

Structures and properties of DIN661 alloy with fine-crystalline additives

The structures and properties of DIN661 alloy with the addition of 1 wt.% of 40% La–60% Ce and with 0.3–0.4 wt.% of Al-based rapidly solidified additives together with SHS Al–Ti mater alloy were compared. Experiments were carried out under industrial conditions. The treatment with the rare earth additives resulted in considerable grain refinement but with worse mechanical properties because of the presence of large crystals of intermetallic phases, primary silicon, α-Al dendrites and greater gas porosity. Less quantities of rapidly solidified additives and SHS Al–Ti mater alloy provided refinement of these phases and better mechanical properties.     

低Re含量第二代柱晶高温合金DZ59的蠕变断裂性能

采用液态金属冷却(LMC)工艺和成分优化设计,制备出一种高温性能优异的低Re含量第二代柱晶高温合金DZ59,通过扫描电镜(SEM),透射电镜(TEM)等方法对其组织特征及蠕变断裂进行了表征,研究了合金的蠕变断裂性能.结果表明,DZ59合金的高温蠕变断裂性能超过一代单晶合金,并接近二代单晶合金的水平.发现柱晶高温合金的二次晶界反应(SGRZ)现象,表明SGRZ受温度和应力的控制,由于增加了合金横向晶界的受力界面,在高负荷下可能成为蠕变空洞萌生和扩展的位置.     

硼在Ni_3Al基合金IC－6中的作用

研究了硼对定向凝固Ｎｉ３Ａｌ基合金ＩＣ－６铸造性能和高温持久性能的影响。试验结果表明：适当增加硼含量可以减少疏松的产生，降低合金的裂纹倾向性，但硼含量增加过多会使合金中析出条状的硼化物，降低合金的高温持久性能。     

热等静压及恢复热处理工艺对DZ125蠕变损伤的影响

选用4种不同参数的热等静压及恢复热处理工艺对DZ125蠕变损伤试样进行显微组织演化的研究,并进行力学性能评价。结果表明:DZ125合金经预持久损伤实验后,显微组织出现了γ′相退化、蠕变孔洞形成等,但是碳化物没有出现由MC型向M_(23)C_6及M6C型分解。此外,热等静压的温度在孔洞愈合过程中作用显著,1200℃及1250℃温度下分别出现了γ′同心筏排结构及合金的初熔现象。同时,通过选取合适的热等静压参数,可以避免内部再结晶的产生。合理的热等静压及恢复热处理工艺可以改善蠕变损伤的显微组织,并使其显微硬度达到原始态水平,且持久寿命得到提高。     

Surface treatment of DZ4 directionally solidified nickel-based superalloy by high current pulsed electron beam

Surface treatment of DZ4 directionally solidified nickel-based superalloy was carried out by using high current pulsed electron beam (HCPEB) technique. Microstructure changes in modified surface layer were characterized together with their corrosion property. It is found that the treated surface becomes rougher with increasing the number of HCPEB pulse due to the formation of craters occurring preferentially in the interdendritic areas. The thickness of remelted layer increased slightly when more HCPEB pulses applied and reached about 3 μm after 10 HCPEB pulses. The corrosion resistance of modified surfaces exhibited an effective improvement when measured in 0.5 mol/L sulfuric acid solution. The factors that influence the corrosion resistance of DZ4 alloy were discussed by considering the surface purification effect featured by HCPEB surface treatment.     

Mechanical properties and microstructures of rapidly solidified Al89.5Ni8Zr2.5 and Al88.5Ni8Ti3.5 alloys

Al89.5Ni8Zr2.5 and Al88.5Ni8Ti3.5 alloys extruded from their rapidly solidified powders have tensile strength more than 800 MPa and Young's modulus about 100 GPa. The extruded Al89.5Ni8Zr2.5 alloy is composed of -Al, Al3Ni and a metastable tetragonal Al3Zr, and the extruded Al88.5Ni8Ti3.5 alloy consists of -Al, Al3Ni and equilibrium Al3Ti. Through investigation on microstructure change of rapidly solidified Al89.5Ni8Zr2.5 and Al88.5Ni8Ti3.5 alloys with temperature, it is found that a new tetragonal Al3Zr phase, together with -Al and Al3Ni precipitates from the supersaturated -Al phase in the rapidly solidified Al89.5Ni8Zr2.5 alloy at around 603 K and an equilibrium Al3Ti, together with -Al and Al3Ni forms from the supersaturated -Al phase in the rapidly solidified Al88.5Ni8Ti3.5 alloy at about 523 K. The lattice parameters of the new metastable tetragonal Al3Zr phase were calculated to be a=0.3896 nm and c=0.9006 nm. Both the metastable tetragonal Al3Zr and equilibrium Al3Ti phases keep a nano grain size, less than 50 nm even at 773 K. The existence of the nano scale Al3Zr, Al3Ti phases and fine grains of -Al, Al3Ni phases is the reason that Al89.5Ni8Zr2.5 and Al88.5Ni8Ti3.5 alloys have the high strength. © 1998 Chapman & Hall     

DZ68合金的持久性能研究

为满足海空环境下服役的航空发动机使用要求,中国科学院金属研究所研制出了一种新型镍基高温合金DZ68.测定了合金的持久性能,采用扫描电镜、透射电镜等仪器观察了DZ68合金的微观组织.研究发现,DZ68合金的持久性能水平与DZ125合金相当.温度低于760 ℃时,持久样品组织中的γ'没有形筏;随着温度升高,γ'之间形筏;相...     

纯净化DZ125合金返回料研究

在工业化生产型真空感应炉中,对定向高温合金DZ125返回料净化技术进行研究,用电子束纽扣法测定夹杂数量,并对净化后的100%返回料锭和常规工艺生产的100%新料锭在纯净度、化学成分、力学性能和铸造性能方面进行对比.结果表明:净化技术显著降低返回料中的氧化夹杂含量,净化后的100%返回料锭和100%新料锭相比,氧化夹杂数量稍有降低,持久性能略有提高,化学成分、室温拉伸性能和铸造性能均相当.     

Carbide Behavior during High Temperature Creep in DZ40M Co-base Superalloy

1.IntroductionDZ40MalloyisadirectionallysolidifiedCo-basesuperalloy,whichwaslatelydevelopedintheInstituteofMetalResearch,ChineseAcademy0fS.i....,[1].ComparedwiththeclassicX-40alloy,DZ4OMal-loypossessesahigherstrengthandahigherincipi-entmeltingpoiat.ServicetemperaturecanincreaJsebyabout450C[2].LikeotherC0-basesuperalloys,carbideisa1s0them0stimp0rtant"second"phaseinDZ40Mall0yandcanc0ntributesignificantlytostrengthening.Itisessentialt0understandcarbidebehaviourunderloadingathightemperatu…     

Influence of high-temperature air pre-exposure on mechanical strength of a directionally solidified cobalt-base superalloy

The present work investigated the influence of air pre-exposure at 850°C for 1000 h on the mechanical properties and microstructures of the directionally solidified cobalt-base alloy DZ40M. The results show that the air pre-exposure did not embrittle the alloy, but resulted in a marked strengthening. Microstructural observations and energy dispersive X-ray spectroscopy (EDS) indicates that the air pre-exposure caused a substantial external and internal oxidation, which is assumed to protect the alloy from being oxidized further and make a significant contribution to alloy strengthening, respectively. The immunity of the alloy to air embrittlement is attributed to elimination of transverse grain boundaries by directional solidification.     

悬浮炉法定向凝固Ti_3Al+Ti_5Si_3双相合金

采用光学悬浮炉法生长Ｔｉ３Ａｌ＋Ｔｉ５Ｓｉ３双相合金的定向凝固样品。结果表明，定向凝固样品的组织与铸态组织相比更接近于平衡态，径向定向凝固态样品组织不均匀，在高的生长速率下Ｔｉ５Ｓｉ３相沿着生长方向分布。     

Wettability of CuNi-Ti Alloys on Si_3N_4 and Interfacial Reaction Products

Based on the alloy Cu55Ni45 (at pct), holding the proportion of Cu to Ni in constant and in the temperature range of 1233~1573 K, the wetting angles of CuNi-0~56 at pct Ti alloys on Si3N4 have been measured by the sessile drop method. With the increase of Ti content, the wetting angles decreased. The equilibrium wetting angle was 5° when Ti content ≥32 at pct.In the case of same Ti content, the activity of Ti in CuNiTi alloy was weaker than that in CuTi alloy The cross-section of the CuNiTi-Si3N4 interface and the elements distribution were examined by scanning electron microscope with X-ray wave-dispersion spectrometer, and the reaction products formed at the interface were determined by X-ray diffiaction analysis method.     

Relationship between η phase formation and solidification rate in directionally solidified IN792 + Hf alloy

Abstract

The effect of solidification rate on the formation of η phase in a directionally solidified IN792 + Hf superalloy was studied. A Cr rich ‘precipitate free zone’ adjacent to the eutectic (γ + γ′) was noticed in the quenched directionally solidified microstructure of the alloy. The formation of the precipitate free zone was due to the solidification of eutectic (γ + γ′) which consumed a large amount of the γ′ forming elements and increased the ratio of (Ti + Hf + Ta + W)/Al in the residual liquid. The high ratio of (Ti + Hf + Ta + W)/Al in the final residual liquid induced the formation of η phase and hence η phase always appeared at the boundary between the eutectic regions and the dendrite core regions. The ratio of (Ti + Hf + Ta + W)/Al was decreased by the diffusion of elements between the residual liquid and the surrounding area. A lower solidification rate favoured the back diffusion and decreased the ratio of (Ti + Hf + Ta + W)/Al in the residual liquid, and hence reduced the formation of η phase.     

Effect of Cr addition on microstructures and nanohardness of rapidly solidified Ti–48Al alloy

Abstract

In this present work, the microstructure and nanohardness of rapidly solidified Ti–48 at-%Al alloy with various Cr additions were experimentally investigated using the single roller melt spinning technique. Ti–48Al alloy with various Cr additions were prepared by arc melting for comparison. In the arc melted alloy, the volume fraction of the interdendritic γ phase decreases, and the lamellar structure and the B2 phase increase with the increase in Cr addition. After rapid solidification, the Ti–48Al alloy consists of the γ phase and α₂ the phase, with the γ phase as the matrix. The α₂ phase exists as particles or in lamellar structure, which embed in the matrix. With 2 at-%Cr addition, the alloy ribbons mainly consist of equiaxial α₂ grains and small particles of the B2 phase, with few lamellar structures occasionally found at the triple grain boundary. Increasing Cr content to 4 at-%, the grain size of the B2 phase increases, and lamellar structures disappear. The change in nanohardness was discussed based on the microstructural observations. It shows a certain increase in the nanohardness as Cr content increases to 4 at-%. This can be attributed to the changes in the microstructures.     

Zr 对 DZ38合金凝固行为和持久性能的影响(英文)

研究了普通定向凝固 DZ38高温合金中,Zr 含量对 DZ38合金凝固行为和持久性能的影响。结果表明,微量元素 Zr 严重影响合金的凝固偏析,Zr 含量超过0.03wt-%时,合金中γ+γ′共晶的析出最明显增加,合金偏析严重,因而降低了合金的初熔和终凝温度;降低 Zr 含量,合金的持久寿命明显提高,特别是无 Zr 合金的横向持久性能比普通 DZ38(含0.057wt-%Zr)合金提高一倍以上。     

The castability of ternary Ni-Cu-Mn alloys for crown and bridge applications

An evaluation of the castability of ternary Ni-Cu-Mn alloys was made for crown and bridge applications. The castability values were compared with those of commercial nickel-based alloys, and the effect of air-venting on the castability was examined. The result that a significant difference is found between ternary alloys and commercial high-fusing alloy shows that the most castable alloys are the ternary ones. When using air-venting within the investment mould, the ternary alloys had more-complete casting than their values in an investment mould without venting.     

钛合金表面Ni-P-PTFE自润滑复合镀层的制备及其摩擦磨损性能

为提高钛合金零部件的使用寿命,以传统的化学镀Ni-P合金工艺为基础,通过添加PTFE粒子使其均匀分布在Ni-P合金镀层中,在钛合金基体上制备了具有耐磨、减摩性能的自润滑复合镀层;分析了PTFE乳液浓度、表面活性剂浓度等参数对复合镀层中PTFE微粒子含量的影响规律;采用SEM、EDS和XRD等手段对复合镀层的微观形貌、相结构和成分进行了分析;研究了不同PTFE含量复合镀层及钛合金基体在相同载荷下的摩擦磨损性能。结果表明:Ni-P-PTFE复合镀层具有良好的减摩耐磨性能,当膜层中PTFE微粒子的含量为20.4%(体积分数)时,钛合金表面的摩擦系数降至0.2左右,而磨损量也显著减小。     

Effect of casting method on castability of titanium and dental alloys

Titanium, once considered to be difficult to cast because of its relatively high melting point and strong chemical affinity, can now be acceptably cast using newly developed casting apparatus. The objectives of this study were to examine the castability of commercially pure (CP) titanium using an ultra high-speed centrifugal casting machine and a pressure difference-type casting unit and to compare the castability of titanium with that of conventional dental casting alloys. To determine castability, two types of patterns were used: a mesh pattern of 22 × 24 mm cut polyether thread sieve, and a saucer pattern (24 mm diameter) perforated to create four T-shaped ends. The casting equipment significantly affected the mold filling of both patterns . The castability indices obtained from both patterns of CP titanium cast in the centrifugal casting machine were significantly better than the indices of the castings produced in the pressure-difference casting unit. The radiographs of the saucer pattern cast in the centrifugal casting machine showed some pores that were fewer and smaller in size than the pores found in castings made in the pressure-difference unit. When the ultra high-speed centrifugal casting machine was used with the manufacturers recommended mold material, the castability of titanium was similar to that of gold alloy or Ni-Cr alloy cast by conventional means.