等离子旋转电极雾化FGH95高温合金原始粉末颗粒中碳化物的研究

利用扫描电镜（SEM）和透射电镜（TEM）对等离子旋转电极雾化（PREP）FGH95高温合金原始粉末颗粒中的碳化物进行研究，并分析了PREP FGH95合金原始粉末颗粒中碳化物在凝固过程中的形成机理，结果表明：粉末颗粒内部中存在MC′型碳化物及微量Laves相和M3B2相， MC′型碳化物形态有块状，条状，花朵状，草书状，粉末颗粒的冷却速率以及已凝固基体在枝晶间所产生的内应力，是导致粉末颗粒中MC′型碳化物形态多样，复杂的一个重要原因。     

高温固溶热处理对HIP态FGH96合金中碳化物影响规律的体视学研究

利用金相显微镜,扫描电镜和透射电镜并结合体视学基本原理,对在不同固溶温度和冷却方式(空冷和炉冷)下热等静压(HIP)态FGH96合金中碳化物的数量、空间分布及尺寸分布等进行了定量表征和对比研究。结果表明:HIP态FGH96合金中碳化物主要为富Nb和Ti的MC,在原始颗粒边界(PPB)上分布的碳化物主要为块状,在PPB区域以外分布的碳化物主要由块状和花状MC组成。在1180℃以下进行固溶热处理时,碳化物含量增加并且加剧了合金中的PPB;当固溶温度达到1180℃以上时,随着固溶温度的升高,合金中碳化物数量减少,PPB逐渐消失。1200℃固溶后炉冷,固溶在基体中的碳主要以非PPB碳化物形式重新析出,会导致合金中PPB碳化物数量的降低,即使合金中的碳化物总量与固溶热处理前几乎相同。另外,空冷合金中PPB碳化物尺寸为单峰分布,而炉冷合金中则表现为双峰,后者与炉冷过程中碳化物能够重新析出密切相关。     

一种多元低合金高碳钢的热处理组织及硬度的研究

对一种低合金高碳钢(0.81C,0.65Cr,0.89W,0.54Mo,0.23V)热处理组织及硬度研究表明,该钢退火具有多类型碳化物(M3C,M7C3,M23C6,M6C和MC),在800～840℃区间退火,处于γ相低温区原碳化物部分溶解和新碳化物重新形核生长过程,使碳化物颗粒超细化,平均尺寸0.33～0.34 μm.淬火时,因M3C、M23C6溶解于奥氏体的速度较快,在840～860℃淬火时,硬度可达HRC63～65;未溶碳化物M6C和MC(VC)有利于马氏体细化,但因其数量较少,淬火最高温度不易超过880℃.该钢在低温和中温回火有较好的抗回火性能,并能有效地促进残余奥氏体转变.该钢热处理过程组织结构特征能较好地以相平衡热力学计算结果进行解释.     

消失模铸渗法制备复合材料的研究

研究了消失模铸渗法中合金颗粒粒度，粘结剂含量、复合熔剂含量和浇注温度等因素对铸渗工艺的影响，给出了合适的铸渗涂层涂料配比，制备了铸铁HT200表面渗铬复合材料，分析了铸渗层的组织和性能，结果表明合金化涂料配比比较优方案为Cr-Fe粉末粒度为0．127－0．181mm，水溶性酚醛树脂含量为2％（质量分数），复合熔剂为7．5％（质量分数）以及适量水和微量添加剂，浇注温度的适宜范围为1400－1500摄氏度。影响消失模铸渗工艺的各因素主次顺序依次为浇注温度，合金粉末粒度，粘结剂含量和复合熔剂含量，铸渗层由外向里可分为3个区，碳化物类型由M7C3向M3C转变，且硬度逐渐降低，表面合金化层的耐磨性为正火45＃钢的2．8倍。     

轧辊用高速钢中碳化物研究

本文利用扫描电镜、能谱分析对三种轧辊用高速钢的组织中碳化物进行了研究,并分析了VC形态与高速钢化学成分之间的关系。结果表明：轧辊用高速钢组织包括马氏体基体,残余奥氏体和各种类型碳化物,如粒状或小块状的MC型碳化物,网状的M7G型碳化物,鱼骨状的M6C型碳化物以及其他复合型碳化物,各种碳化物含有的合金元素以及显微硬度不同;在研究范围内（Weq≤10）,晶粒尺寸是随钨当量的升高而变小;根据V含量不同,VC会出现不同形貌进而影响高速钢性能。     

高温扩散退火处理对FGH96粉末高温合金PPB的影响

研究了亚固相线温度扩散退火处理对FGH96粉末高温合金原始颗粒边界(PPB)的影响,结果表明,试验用热等静压(HIP)态FGH96试样中所存在的PPB主要由富Ti和Nb的MC型碳化物以及少量的氧化物组成.试样经1230℃×8h/AC扩散退火处理后并不能完全消除PPB,但部分碳化物溶解,PPB从连续网膜转变成离散的颗粒状,显微组织中PPB明显减轻.试样经HIP+1150℃×30min/WC处理后在PPB较严重的区域出现裂纹,主要沿PPB扩展;退火态试样经1230℃×30min/WC处理后裂纹相对较细,其主要沿晶界扩展.     

Inconel 625合金中析出相演变研究进展EI北大核心CSCD

本文综述了Inconel 625合金析出相的析出与演变行为,重点介绍了该合金不同类型析出相包括γ′相、γ″相、δ相、Ni2(Cr,Mo)相以及MC,M6C,M23C6型碳化物和Laves相;阐明不同成形工艺、热处理及高温蠕变过程中析出相的析出与演化行为,论述不同类型的析出相对合金性能的影响;指出Inconel 625合金快速成形及焊接过程中产生裂纹的主要因素,并提出未来重要的发展方向是如何通过选择与控制相析出来进一步提高Inconel 625合金的热强性和热疲劳性能。     

真空熔炼过程ZrO_2过滤器对FGH96净化作用研究

针对粉末高温合金FGH96真空熔炼浇铸过程,进行夹杂过滤,分析在真空状态下,不同目数ZrO_2过滤器对FGH96粉末高温合金的过滤效果,通过浮渣实验观察浮渣面积有逐渐减小的趋势。通过大样电解实验,定量分析了不同孔径ZrO_2过滤器对合金的净化效果。并且通过EDS分析合金夹杂的成分。本文从多方面评价了真空熔炼过程中不同孔径ZrO_2过滤器对粉末高温合金FGH96的净化效果。     

原始颗粒边界对粉末热等静压成形FGH97合金性能的影响

目的 基于粉末冶金近净成形工艺,研究原始颗粒边界（PPBs）对FGH97合金力学性能的影响,并验证热处理和二次热等静压工艺能否消除PPBs。方法 采用等离子旋转电极雾化法制备FGH97合金粉末,分别在1 200℃/120 MPa/2 h和1 200℃/140 MPa/3 h条件下进行热等静压成形。先后对FGH97合金进行固溶（1 200℃/4 h/炉冷）和时效（910℃/3 h/空冷+750℃/8 h/空冷+700℃/17 h/空冷）热处理,并对热处理后的样品进行二次热等静压（制度为1 200℃/140 MPa/3 h）。对上述实验前后的FGH97合金显微组织进行表征,使用Photoshop软件计算PPBs的占比,研究热处理和二次热等静压工艺对PPBs的消除作用。结合力学性能测试研究PPBs对合金性能的影响。结果 当采用压力更高、保温时间更长的热等静压制度时,制备得到的FGH97合金PPBs占比更少、力学性能更好,其PPBs占比为5.6%,室温抗拉强度为1 412 MPa,屈服强度为947 MPa,伸长率为16%。经热处理后,FGH97合金中PPBs的占比下降至3.0%,该合金在650...     

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。     

石墨烯增强镍基粉末高温合金复合材料的力学性能

采用湿混法将石墨烯纳米片分散到高温合金粉末中,并采用热等静压+热挤压+等温锻造+热处理的方法制备出FGH96镍基粉末高温合金。结果表明:石墨烯纳米片在高温合金中分散均匀,初步发现在后续的热工艺过程中并未发生变性;添加0.1%(质量分数)的石墨烯后,室温抗拉强度和屈服强度分别提高了58MPa和43MPa,塑性从21.0%提高到37.3%;650℃条件下抗拉强度和屈服强度分别提高了58MPa和28MPa,塑性从18.5%提高到26.5%。此外对石墨烯增强FGH96镍基高温合金力学性能的作用机制也进行了进一步分析。     

Rejuvenation of the microstructure and mechanical properties of a service-exposed IN939 superalloy by heat treatments

Effect of heat treatment on the recovery of microstructure and mechanical properties of a service-exposed IN939 superalloy was studied. Four-stage heat treatment was performed on the service-exposed alloy. The microstructures of the service-exposed and rejuvenated alloys were examined by optical and scanning electron microscopes. The hardness, tension, and stress-rupture tests were carried out to characterise the mechanical properties. The results showed that the heat treatment could rejuvenate the microstructure of the alloy that was deteriorated during the service at high temperatures. Decomposed MC carbides were transformed to new fine carbides, continuous M23C6 carbides were dissolved and new discontinuous carbides along the grain boundaries were regenerated and, finally, the fine γ? particles were reformed. The microstructural recovery resulted in an increase in the hardness and ultimate tensile strength of the alloy. The results also showed that the creep behavior of the alloy at a testing temperature of 850°C could be improved by the heat treatment.     

Formation of Re-containing Carbides in a Second Generation Directionally Solidified Ni Base Superalloy

The precipitates at grain boundary in a directionally solidified Ni base superalloy after heat treatment, aging at 975℃, and creep rupture test have been characterized. Besides the primary MC carbides and fine particles of μ phase, the Re-containing M23C6 was observed. The precipitation kinetics revealed that the formation of M23C6 was associated with the dissolution of μ phase and MC carbides. TEM image shows that the continuous precipitation of M23C6 particles effectively hinders the dislocation movement ...     

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…     

Effect of powder preparation technology on the hot deformation behavior of HIPed P/M nickel-base superalloy FGH96

In this paper, the hot deformation characteristics of P/M nickel-base superalloy FGH96 prepared by different powder preparation technologies were studied in the deformation temperature range from 1000 °C to 1100 °C and the strain rate range from 0.001 s⁻¹ to 1 s⁻¹ using hot compression tests. The peak stress vs. deformation temperature curves and the peak stress vs. strain rate curves were established, respectively. The results show that the specimens prepared by plasma rotation electric pole (PREP) powder were more sensitive to deformation temperature and strain rate. On the basis of the dynamic material model, the processing maps for hot working were developed. The activation energies and Zener-Hollomon parameters were obtained by linear statistical regression method. For the specimens prepared by PREP powder, the peaks of power dissipation mainly located in lower temperature domain (1000-1030 °C), and the efficiencies of power dissipation (EPD) obtained in the strain range from 0.1 to 0.7 were essentially similar. This indicated that strain had a slight influence on processing maps. For the specimens prepared by argon atomization (AA) powder, the effects of strain on EPD and instability domains were significant. The lower activation energies and Z values indicated that the workability of the specimens prepared by AA powder is better than that prepared by PREP powder. Moreover, it was found that effects of the heat treatment time on activation energy and Zener-Hollomon parameter were significant. With the increase of heat treatment time, the dislocation density and the volume fraction of precipitation phase gradually decreased. Microstructural observation demonstrated that the phenomenon of recrystallized grains coarsening existed in the specimens prepared by longer heat treatment time. The heat treatment time of the specimens prepared by AA powder should be appropriately shortened in order to prevent recrystallized grains coarsening.     

Mechanical Properties and Strain Hardening Behavior of Few-Layered Graphene Nanosheets-Reinforced Powder Metallurgy Nickel-Based Superalloy Metal Matrix Composites

Herein, few-layered graphene nanosheets (GNS) with approximately 3, 6, or 9 layers are used to reinforce high-performance nickel-based superalloy metal matrix composite. A powder metallurgy method comprising solution-mixing, hot isostatic pressing, and thermal processing is used to prepare GNS-FGH96 composites with different numbers of GNS layers as well as referential FGH96 matrix materials. Compared with those of unreinforced FGH96, the mechanical properties of the GNS-FGH96 composites are enhanced, specifically, the ≈6 layers GNS-FGH96 composite exhibits an ultimate tensile strength of 1660 MPa and a yield strength of 1229 MPa, which are 9.79% and 6.87% higher, respectively, than those without the addition of GNS. Furthermore, the ≈6 layers GNS-FGH96 composite exhibits the highest elongation-at-fracture of 29.9%. The as-prepared GNS-FGH96 composites show a good balance of strength and ductility owing to the increased dislocation density between the FGH96 matrix and GNS reinforcement interface area, as well as the high structural integrity of the GNS. Thus, this study provides a novel approach for designing and creating high-performance graphene-reinforced FGH96 metal matrix composites that exhibit exceptional strength and toughness.     

SiO2在FGH96高温合金中的遗传特征

研究了SiO2颗粒在FGH96高温合金各不同工艺状态中的行为特征,结果表明:经热等静压处理后,SiO2尖角分明的特征消失,在界面处有反应过渡区生成,变成了一种"复合"非金属夹杂物.反应的驱动力为粉末和SiO2颗粒的表面能及在热等静压过程中球形粉末变形产生的应变能.在随后的各工艺状态中,SiO2在形貌、尺寸和元素分布等方面表现出了一定的行为特征.     

Effect of heat treatment on the micro-indentation behavior of powder metallurgy nickel based superalloy FGH96

The influences of solution treatment temperature on microstructure and micromechanics of P/M nickel-base superalloy FGH96 were investigated by micro-indentation methods. The alloy was heat-treated at the temperatures of 1050 °C, 1150 °C, 1220 °C and 1310 °C, respectively. The micro-indentation tests were conducted in the indenter load range from 500 mN to 4500 mN and the loading rate range from 5.19 mN/s to 103.71 mN/s at room temperature by using a sharp Berkovich indenter. The influence of solution treatment temperature on microstructure was analyzed based on microstructural observations using both optical and scanning electron microscope. The micro-hardness, Young’s modulus and yield stress were obtained by means of Oliver–Pharr method and reverse analysis algorithms, respectively. The results show that both of micro-hardness and Young’s modulus are significantly affected by indentation depth and solution treatment temperature. Based on microstructure analysis, these effects were attributed to the changes of precipitate properties, e.g., size, distribution and morphology, and the relationship between microstructure and micromechanics was established. Then, the deformation mechanism was explained on the basis of dislocation–dislocation and dislocation–precipitate interactions. In this paper, the descending Young’s modulus was related to localized stress concentration and microcrack propagation. The results reveal that the damage variable is high for P/M nickel-base superalloy FGH96 after high temperature solution treatments.     

热等静压FGH95粉末涡轮盘

采用氩气雾化和等离子旋转电极雾化两种制粉工艺制备的ＦＧＨ９５粉末和双韧化（颗粒界面韧化＋热处理强韧化）热等静压近尺寸成形盘件制备工艺,制备了ＦＧＨ９５粉末涡轮盘。性能达到国外同类合金的Ａ级水平并装机通过了发动机的盘件结构试验与试车。     

镍基钎料钎焊K465高温合金大间隙接头组织与性能研究

K465镍基高温合金为母材,FGH95镍基合金粉为预填粉末,采用预填高熔点粉末的方法对0.5mm大间隙接头进行钎焊,研究不同保温时间对钎缝组织与接头性能的影响。结果表明:1220℃保温0.5h获得的钎缝组织由合金粉颗粒及颗粒间的相构成,颗粒内为γ和γ′两相组织,颗粒间为γ和γ′两相为基体的硼化物、硅化物及γ+γ′共晶组织;随钎焊保温时间延长,合金粉颗粒长大,化合物相及γ+γ′共晶组织合并、总量减少;钎焊保温时间为0.5~16h时,接头平均持久寿命由31.59h提高至54.58h,但不易获得高性能等温凝固接头。