铁基金温合金GH2871成分对组织和性能的影响

开发出新型含０．５％Ｎｂ，并以Ｗ，Ｍｏ复合固溶强化的２８Ｎｉ－１４Ｃｒ－１．０Ｗｏ－２．１Ｔｉ－Ｎｂ－Ａｌ铁基高温合金ＧＨ２８７１。该合金的综合机械性能优于同类２５Ｎｉ－１５Ｃｒ铁基高温合金。     

铁基高温合金GH2871成分对组织和性能的影响

开发出新型含０．５％Ｎｂ，并以Ｗ、Ｍｏ复合固溶强化的２８Ｎｉ－１４Ｃｒ－１．ＯＷ－１．５Ｍｏ－２．１Ｔｉ－Ｎｂ－Ａｌ铁基高温合金ＧＨ２８７１。该合金的综合机械性能优于同类２５Ｎｉ－１５Ｃｒ铁基高温合金。     

FeNiCrAlRE高温耐热合金研制

从Ｆｅ－（８～４０）Ｎｉ－（１０～３０）Ｃｒ－（３～８）Ａｌ合金中筛选出３种γ相合金，它们的抗氧化性与ＦｅＣｒＡｌ合金相同，热强性，抗脆化能力与塑性与Ｃｒ２０Ｎｉ８０合金相当，而且有良好的铸造，冷加工和焊接性能，合金生产成本只有Ｃｒ２０Ｎｉ８０的１／３，在耐热和电热领域有重要的应用前景，选出了２种γ＋α双相合金，与ＦｅＣｒＡｌ合金相比，其抗氧性相同，热强性和抗脆化能力略高，塑性稍低，可用于高使用温     

NiCr40合金再结晶的研究

ＮｉＣｒ_（４０）合金再结晶的研究张兴维，李勇军，王永兰，张宝珍，丁瑞鑫（北京有色金属研究总院１０００８８）关键词：ＮｉＣｒ_（４０），再结晶组织ＮｉＣｒ４０合金是制备集成电路网络电阻薄膜用溅射靶材。从相图［１］上看出ＮｉＣｒ４０合金大约在９５０℃以下...     

FeNiCrAlRE高使用温度耐热合金研制

从Ｆｅ－（８～４０）Ｎｉ（１０～３０）Ｃｒ－（３～８）Ａｌ合金中筛选出３种γ相合金，它们的抗氧化性与ＦｅＣｒＡｌ合金相同，热强性、抗脆化能力和塑性与Ｃｒ２０Ｎｉ８０合金相当，而且有良好的铸造、冷加工和焊接性能，热加工工艺已被掌握。合金生产成本为Ｃｒ２０Ｎｉ８０的１／３，在耐热和电热领域有重要的应用前景。选出了２种γ＋α双相合金，与ＦｅＣｒＡｌ合金相比，其抗氧化性相同，热强性和抗脆化能力略高，塑性稍低，可用于高使用温度耐热结构元件。α相合金塑性很低，但可从它极高的强度和硬度特性开发实际应用。添加稀土元素对发展新合金起关键作用。     

FeNiCrAIRE高温耐热合金研制

从Ｆｅ－（８～４０）Ｎｉ－（１０～３０）Ｃｒ－（３～８）Ａｌ合金中筛选出３种γ相合主，它们的抗氧化性与ＦｅＣｒＡｌ合金相同，热强性、抗脆化能力和塑性与Ｃｒ_(２０Ｎｉ_(８０)合金相当，而且有良好的铸造、冷加工和焊接性能，合金生力成本只有Ｃｒ_(２０)Ｎｉ_(８０)的１／３，在耐热和电热领域有重要的应用前景。选出了２种γ＋α双相合主，与ＦｅＣｒＡｌ合金相比，其抗氧化性相同，热强性和抗脆化能力略高，塑性稍低，可用于高使用温度耐热结构元件。α相合金塑性很低，但可从它极高的强度和硬度特性开发实际应用。添加稀土元素对发展新合金起关键作用．     

稀土合金的金相样品制备及组织分析

以Ｌａ－Ｃｏ－Ｎｉ三元系和Ｎｄ－Ｃｕ、Ｇｄ－ＣＵ二元系为例,介绍了稀土合金相试样的制备步骤和原则,给出了用该方法制作的５Ｌａ－７３Ｃｏ－２２Ｎｉ、５Ｌａ－８９Ｃｏ－６Ｎｉ、２５．６Ｌａ－３４Ｃｏ－４０．４Ｎｉ、Ｎｄ－６９Ｃｕ、Ｇｄ－１２Ｃｕ等成分合金的金相照片,并进行了适当的分析。     

超低碳Cr26－Ni28－Mo5－Cu3－Nb0．35铸造不锈钢的组织和耐蚀性能

用金相、透射电子显微镜、电子探针与扫描电镜分析研究得出，超低碳Ｃｒ２６－Ｎｉ２８－Ｍｏ５－Ｃｕ３－Ｎｂ０．３５不锈钢铸态组织中含有σ相，经８５０～１１２０℃热处理均可形成σ相，包括（Ｆｅ－Ｃｒ）σ相，（Ｆｅ－Ｍｏ）σ相和（Ｃｒ－Ｎｉ－Ｓｉ）σ相；８５０℃左右有Ｍ６Ｃ型碳化物和ＮｂＣ析出。该钢经１１５０℃２ｈ水冷固溶处理后，具有优良的耐腐蚀性能。     

超低碳Cr26—Ni28—Mo5—Cu3—Nb0.35铸造不锈钢的组织和耐蚀性能

用金相、透射电子显微镜、电子探针与扫描电镜分析研究得出超低碳Ｃｒ２６－Ｎｉ２８－Ｍｏ５－Ｃｕ３－Ｎｂ０．３５不锈钢铸态组织中含有σ相，经８５０￣１１２０℃热处理均可形成σ相，包括（Ｆｅ－Ｃｒ）σ相，（Ｆｅ－Ｍｏ）σ相和（Ｃｒ－Ｎｉ－Ｓｉ）σ相，８５０℃左右有Ｍ６Ｃ型碳化物和ＮｂＣ析出。该钢经１１５０℃２ｈ水冷固溶处理后，具有优良的耐腐蚀性能。     

新型电热合金Fe3Al的研制

通过对Ｆｅ３Ａｌ基合金的电阻率、热膨胀系数的测定及抗氧化性能、高温力学性能的研究发现,Ｆｅ３Ａｌ基合金的室温电阻率高于Ｎｉ８０Ｃｒ２０、０Ｃｒ２５Ａｌ５合金。当温度低于９００℃时,其抗氧化性能与二种对比合金相当,温度大于９００℃时,其抗氧化性能明显优于对比合金。高温断裂强度高于０Ｃｒ２５Ａｌ５合金,而与Ｎｉ８０Ｃｒ２０合金相当。Ｆｅ３Ａｌ合金是一种比较理想的电热体材料。     

时效处理对Cr20Ni32AlTi合金室温冲击性能的影响

 研究了铁镍基耐热耐蚀合金Cr20Ni32AlTi在1150℃、15min固溶处理并经450~850℃、05~5h的时效处理后室温冲击性能的变化规律。结果表明,450℃时效冲击性能最好。随时效温度升高,时效时间延长,冲击性能下降。450~850℃时效时,在合金晶界上有碳化物M23C6析出,且随温度增加和时间延长,析出增加。850℃时冲击功最低,此时碳化物M23C6析出相呈连续颗粒状析出,布满整个晶界。且观察到一些部位碳化物M23C6析出相形成薄膜,冲击时因基体变形而脆断成条块状。     

700℃时效过程中HR100合金的碳化物析出行为

对经700℃时效不同时间后的镍基HR100合金中的析出相进行了定性与定量分析,研究了HR100合金中的碳化物在长期时效过程中的析出行为。结果表明,HR100合金中的M_6C型碳化物为亚稳相。在长期时效过程中,随着合金元素的扩散,HR100合金中的M_6C会逐渐转化为M_(12)C。而且在700℃时效1万h过程中,HR100合金中的碳化物的析出行为主要分3个阶段:快速析出与M_6C→M_(12)C转化阶段,相对稳定阶段,M_(12)C和M23C6进一步析出、长大阶段。另外,对不同类型碳化物中的合金元素配比在长期时效过程中的变化进行了分析,发现在(M_6C+M_(12)C)的粗化过程中,Cr元素和Mo元素起主要作用;而在M_(23)C_6的粗化过程中,Cr元素起主要作用。     

合金碳化物M23 C6的磁性及磁致磁性

利用第一性原理研究了碳化物M23 C6 (M=Fe,Cr)的晶胞结构、磁矩和态密度,并结合魏氏分子场理论分析了磁场作用下一些碳化物的磁致磁性.结果 显示:Fe20 Cr3 C6碳化物中的Fe3和Fe4原子连接组成稳定的晶格框架,Cr1、Cr2和C原子位于框架中心;Fe20 Cr3 C6的磁性主要来源于Fe和Cr原子的3...     

Thermodynamic aspects of the modification of low-chromium cast iron

Thermodynamic aspects of the modification of low-chromium (3–5% Cr) cast iron with Fe-Si-Mg alloy are considered. Such modification has an effect similar to that obtained on alloying: a phase transformation occurs in the structure of cast iron. Instead of a ledeburite eutectic with simple cementite Fe₃C and alloyed cementite (Fe, Cr)₃C, a eutectic with carbide (Cr, Fe)₇C₃ is formed. This carbide usually appears with at least 8–9% Cr in the cast iron. This effect may be attributed to the quasi-equilibrium state of the cast iron in treatment by a modifying agent. On the one hand, the melt is in a nonequilibrium state, because it contains many microzones with high Si and Mg content. On the other, the melt within the microzones may be regarded as in a quasi-equilibrium state. Within these microzones, on account of the high carbon activity, conditions are created for the formation of the carbide (Cr, Fe)₇Cr₃, as is confirmed by thermodynamic calculations. This effect permits marked improvement in the properties of cast iron, without significant expense.     

Cr20Ni32AlTi合金平衡相的热力学模拟计算与分析

通过热力学计算软件Thermo-Calc与相应的Ni基数据库,进行了耐热耐蚀合金Cr20Ni32A1Ti(％:0.10C、0.83Mn、0.56Si、＜0.005P、0.013S、20.89Cr、32.60Ni、0.26A1、0.39Ti、0.009 0N、0.076Cu)化学成分对主要析出相影响的研究,并分析了合金成分对合金初熔点和终熔点的影响.通过SEM、TEM和X射线能谱法对Cr20Ni32AlTi合金的组织和析出相成分进行了实验研究.结果表明,Cr20Ni32AlTi合金的主要析出相为M23C6和M(CN)碳化物,C含量(0.02％～0.10％)显著影响M23C6碳化物的析出量和开始析出温度;Cr含量(20％～22％)和C含量均影响合金的初熔点和终熔点.     

钕对NiAl基共晶合金高温流变行为的影响

 研究了钕对NiAl 28Cr 55Mo 05Hf共晶合金显微组织及高温流变行为的影响。结果表明：NiAl 28Cr 55Mo 05Hf基体合金是由黑色的NiAl相和灰白色的Cr(Mo)相组成的共晶组织，在相界处聚集有白色的Ni2AlHf(Heusler)相，加入稀土钕可细化组织；NiAl 28Cr 55Mo 05Hf(wNd=005%)合金在较高的应变速率(=194×10-2 s-1和=194×10-3 s-1)下，含稀土合金的流变应力大于不含稀土合金的流变应力，而在低应变速率(=194×10-4 s-1)下，这种强化现象消失。幂指数规律和温度补偿的幂指数规律可以很好地描述各种合金的高温压缩流变行为。加入稀土可降低合金的应力指数和变形激活能，这是因为稀土偏聚在相界上，致使相界上的空位浓度发生变化。     

Effect of Heat Treatment on Structure and Wear Re- sistance of High Chromium Cast Steel ContainingBoron

The microstructure, mechanical properties and wear resistance of high chromium cast steel containing boron after different heat treatments were studied by means of the optical microscopy （OM）, the scanning electron microscopy （SEM）, X-ray diffraction （XRD）, hardness, impact toughness, tensile and pin-on-disc abrasion tests. The results show that as cast microstructures of boron-free high chromium steel consist of martensite and a few （Cr, Fe）_7C_3 carbide, and the macro-hardness of boron-free high chromium steel is 55-57 HRC. After 0.5 mass% B was added into high chromium cast steel, as-cast structure transforms into eutectic （Fe, Cr）2B, （Cr, Fe）7 （C, B）a and martensite, and the macro-hardness reaches 58-60 HRC. High temperature quenching leads to the disconnection and isolated distribution of boride, and there are many （Cr,Fe）_23 （C,B）_6 precipitated phases in the quenching structure. Quenching from 1050 ℃, high chromium steel obtained the highest hardness, and the hardness of high chromium cast steel containing boron is higher than that of boron-free high chromium steel. The change of quenching temperature has no obvious effect on impact toughness of high chromium steel, and the increase of quenching temperature leads to tensile strength having an increasing tendency. At the same quenching temperature, the wear resistance of high chromium cast steel containing boron is more excellent than that of boron-free high chromium steel. High chromium cast steel guide containing boron has good performance while using in steel bar mill.     

Development of New Wear-Resistant Surface Coating at Elevated Temperature

Metal matrix composites containing a high vol-ume fraction of carbide particles are frequently usedas wear-resistant materials[1 -4]. For elevated tem-perature service in air ,the oxidation resistance andthe hot hardness of hard particle are the most i mpor-tant factors .In metal carbides ,tungsten carbide andchromiumcarbide can act as hard particles in metalmatrix in order to increase their hot hardness andthe ability of wetting metal matrix. Compared withtungsten carbide ,chromiumcarbide is …     

Chemical composition and structural identification of eutectic carbide in 1 pct Mn ductile iron

Manganese, which may be used in ductile cast iron as a potent hardenability promoter, segregates in the intercellular region. This segregation becomes more severe as a consequence of poor inoculation, low cooling rate, or increasing of nominal Mn content in the alloy. In severely Mn-segregated regions, Mn eutectic carbide may be formed, which has a deteriorating effect on the mechanical properties of casting. In this study, a 1 Pct Mn ductile iron was used to investigate the chemical composition and crystal structure of the Mn eutectic carbide by electron microscopy (scanning and transmission), X-ray, and an electron probe microanalyzer (EPMA). Transmission electron microscope (TEM) and X-ray studies show that the crystal structure of carbide is orthorhombic with lattice parameters ofa = 14.825,b = 11.415, andc = 8.880 (Å). The concentrations of Mn, Si, and Cr in carbide, analyzed by scanning electron microscope-energy-dispersive X-ray spectrometer (SEM-EDX) and transmission electron microscope-energy-dispersive X-ray spectrometer (TEM-EDX), were 5.0 to 7.0, 0.5 to 2.8 and 1.5 to 2.2 (wt Pct), respectively. The ratio of Fe plus other metal atoms to C was calculated from EPMA experiments to be 2.5-2.9. It was shown that by diminishing Mn segregation, precipitated eutectic carbide can be reduced. It is expected that this can be achieved by reducing nominal content of Mn or by increasing nodule count.     

Unidirectional solidification of Co−Cr−C monovariant eutectic alloys

Compositions on the eutectic liquidus line between Co-25 wt pct Cr-3.5 wt pct C and Co-45 wt pct Cr-2.2 wt pct C wherein the simultaneous freezing of a metal matrix and a carbide occur have been solidified unidirectionally. The composite structures formed consist of a cobalt matrix containing substantial amounts of soluble chromium with the carbide phase, (Cr, Co)₇C₃, as an aligned fibrous dispersion. The structure of one monovariant eutectic composition has been examined as a function of solidification velocity. Cellular growth was observed at rates above approximately 4 cm per hr. However, the cell cusps only gradually deepen with increasing growth rate and the carbide phase remains essentially aligned even at 50 cm per hr. The concentration of carbide fibers in the transverse section was measured at various growth rates and was found to be approximately a linear function of rate. The structure of the alloy was also examined by transmission electron microscopy. These results indicate that the preferred growth direction of the carbide is more important than the solid-solid surface energy in controlling the growth.