Fe-Cr-Ni-C四元系奥氏体与碳化物之间的相平衡计算

将Bjorn Uhrenius描述Fe-C基三元合金体系热力学性质的亚点阵模型扩展后应用于Fe-C基四元合金体系,给出了自由能函数关系表达式,并且在Biorn Uhrc-nius对Fe-Cr-C系热力学平衡计算的基础上,再结合Nishizawa对于Cr-Ni二元系给出的交互作用参数,对Fe-Cr-Ni-C系中固溶体和碳化物的两相平衡进行了计算求解。     

脉冲电流对铁基合金凝固组织的影响

利用自行设计的脉冲电流发生装置和高温坩埚炉研究了脉冲电流对Fe70Cr18Ni12合金凝固组织的影响.结果表明,脉冲电流可明显细化Fe70Cr18Ni12合金的凝固组织,使该合金的晶粒尺寸由240 μm细化到1.8 μm;同时脉冲电流处理可改变合金凝固组织中奥氏体相和铁素体相的相对含量.     

铁基合金快淬装置用陶瓷喷嘴的研究

陶瓷喷嘴是制取非晶态金属薄带快淬装置的关键部件之一。铁基合金的快淬工艺要求陶瓷喷嘴在高温下具有化学稳定性、耐冲刷性、抗热震性,且易机械加工。根据喷嘴的材料与工艺的选择试验结果。选用了热压烧结氮化硼(BN)基陶瓷喷嘴。本文叙述了不同材料与工艺制备的喷嘴性能,及使用试验。结果表明,含有氧化物加入物的BN基热压烧结陶瓷喷嘴的各项性能指标,是符合使用要求的。     

Al_2O_3、MgO交互作用对复合铁酸钙生成影响机理

为了探索复合铁酸钙的生成机制以优化烧结工艺,提高烧结矿质量,采用相平衡法研究了准化学平衡条件下Al_2O_3与MgO在烧结中的行为。结果表明,Al_2O_3和MgO的共同存在有利于复合铁酸钙(silico-ferrite of calcium and alminum,简称SFCA)的生成,但存在着交互作用,MgO促进赤铁矿分解生成磁铁矿,Al_2O_3的存在可抑制MgO的作用,减少磁铁矿生成,尤其在Al_2O_3质量分数较高时,MgO促进磁铁矿生成能力降低,促进SFCA生成作用增强。当MgO质量分数为2%时,添加质量分数2%的Al_2O_3矿相中磁铁矿质量分数快速降低,SFCA质量分数快速增加;随着Al_2O_3质量分数升高,SFCA晶面间距减小,晶体结构稳定性增强,有利于SFCA的生成;Al_2O_3质量分数超过3%后,孔洞结构增多,SFCA质量分数增加变缓,磁铁矿质量分数呈降低趋势,赤铁矿质量分数有升高趋势。     

新型铁基合金材料在铝液中耐腐蚀性能的研究

研究新型铁基合金中组成对其抗铝液腐蚀性能的形响，探讨了合金在铝液中的腐蚀机理。实验结果表明：在影响铁基合金在铝液中抗腐蚀的诸因素中，石墨形态的影响是主要的，铬对合金抗腐蚀性能的负作用比较大，少量难对合金的抗腐蚀性能有较大负作用，在一定量以后，对合金的抗腐蚀性能有所改善，铜对合金的抗腐蚀性能影响较小。     

镍的合金化方法对铁基合金组织和力学性能的影响

针对Fe-1.75Ni-0.50Mo-1.5Cu-0.6C粉末冶金合金,采用羰基Ni粉混合和水雾化预合金化两种方法添加Ni元素,研究Ni元素的合金化方式对该合金组织和性能的影响.结果表明:在相同的条件下,由Ni预合金Fe粉制备的烧结合金密度和抗拉强度较低,硬度较高,组织为均匀的珠光体和铁索体混合组织;而由羰基Ni粉混合...     

回火温度对铁基合金组织与力学性能的影响

将真空烧结的铁基合金奥氏体化、油淬后,在600~700℃温度下进行回火处理,保温1 h,空冷。测试回火后合金的硬度和冲击韧性,并用金相显微镜、X射线衍射(XRD)、扫描电镜(SEM)观察和分析合金的组织、结构与断口形貌,研究回火温度对铁基合金组织与力学性能的影响。结果表明:随回火温度升高,第二相碳化物粒子M23C6的含量(质量分数)基本保持不变,约为3.5%;碳化物M6C的数量大幅减少,平均尺寸明显减小,碳化物M6C的第二相强化效果降低,硬度下降,同时基体组织软化,冲击吸收功增大。回火温度为675℃时,铁基合金保持较高的硬度40 HRC,冲击韧性较回火前提高11%。回火处理后的铁基合金断口形貌为典型的沿晶断裂     

数字化技术在铁基合金锰元素可见光谱分析中的应用

使用可见光谱数字化自动分析系统对铁基合金中Mn元素可见光谱进行了分析测定。研究了铁基合金中Mn元素的Mn 478.34 nm和Mn 601.35 nm分析谱线组的特征,并制作了数字化彩色图谱。探索了铁基合金中Mn元素的数字化分析技术,结果可用于铁基合金中Mn元素的定性、定量分析和牌号鉴别。     

数字化技术在铁基合金钨元素可见光谱分析中的应用

使用数字化分析系统对铁基合金中钨元素可见光谱进行了谱图记录和观测分析等应用研究。结果表明,该系统可以有效地解决目前铁基合金中钨元素看谱分析面临的很多问题。借助数字分析系统可大幅度降低看谱镜使用技术难度,还可有效解决材料可见光谱的记录问题,使看谱分析结果具备了可追溯性。该系统可对铁基合金中钨元素分析的所有谱线给出客观的相对强度数据,避免了人眼视觉误差对测试的影响。     

强磁场对铁基合金相变温度和显微组织的影响

The effect of a high magnetic field up to 30 T on phase transformation temperature and microstructure of Fe-based alloys has been reviewed. A high magnetic field accelerates ferrite transformation, changes the morphology of the transformed microstructures and increases the As and A1 temperature. In a magnetic field of 30 T, the A1 temperature increases by about 37.1℃ for Fe-0.8C, the A3 temperature for pure Fe increases by about 33.1 ℃. The measured transformation temperature data are not consistent with calculation results using Weiss molecular field theory. Ferrite grains are elongated and aligned along the direction of magnetic field in Fe-0.4C and Fe-0.6C alloys by ferrite transformation, but elongated and aligned structure was not found in pure Fe, Fe-0.05C alloy and Fe-1.5Mn0.11C-0.1V alloy.     

Effect of compacting pressure on shape retention during supersolidus liquid phase sintering of Cu base alloys

The compacting pressure is one of the key parameters which affects sintering phenomena, such as fragmentation, rearrangement and densification. However, the type of alloy also has a similar significance which should be considered. To demonstrate the effect of the mentioned parameters, two types of copper base alloys, i.e. Cu–9Sn–8Pb and Cu–28Zn, were investigated in the present study. Prealloyed powders were compacted at 100 and 400?MPa, respectively, and sintered in the range of 890–970°C for 20?min. In situ images of the samples were taken at various sintering conditions, and the shapes were recorded. For both materials, in case of compaction at lower pressure, the gravity-induced distortion known as ‘elephant foot’ phenomenon was not observed, and the specimens show shape retention during sintering even at higher temperatures, while samples compacted at 400?MPa showed different responses to the sintering conditions: A-shaped distortion (elephant foot) occurred in the bronze alloy, while in the brass alloy O-shaped distortion was observed.     

Titanium-boride eutectic materials. Structure of the Ti-Nb-B alloys and phase equilibria

The structure of Ti-Nb-B alloys that are cast and annealed at subsolidus temperatures and at 1400°C is experimentally analyzed (x-ray diffraction, metallography, and electron probe microanalysis), and so are temperatures of their phase transformations (differential thermal analysis and pyrometry). No ternary phases are found in the alloys. Projections of solidus and liquidus surfaces, an isothermal section at 1400°C, and a vertical section at 7.5 at.% B are constructed. A reaction scheme is proposed for alloy crystallization. __________ Translated from Poroshkovaya Metallurgiya, Vol. 46, No. 1–2(453), pp. 72–87, 2007.     

Dy对NdFeB永磁合金各向异性的影响

对名义成分为Nd_12.3-xDy_xFe_79.7Nb_0.8Zr_0.8Cu_0.4B₆(x=0,0.5,1.5,2.5)的预合金进行长时间高温退火,将其破碎,取向并粘结.分别沿取向方向和垂直于取向方向测量其磁化曲线.将两曲线延长至相交,交点对应的磁场视为材料的磁晶各向异性场.结果表明:随着Dy含量的增加,合金各向异性场(H_A)呈线性增加.当Dy的原子分数为2.5%时,合金各向异性场达到7536 kA·m^-1;平均每增加1%Dy,各向异性场提高值为200~300 kA·m^-1.     

Titanium-boride eutectic materials: Structure of titanium-rich Ti-Ge-B alloys and phase equilibria at crystallization temperatures

Phase equilibria in the Ti-TiB₂-Ti₅Ge₃ region of the Ti-Ge-B system are experimentally investigated at melting/solidification temperatures using x-ray diffraction, metallography, EMPA, and differential thermal analysis. The phase diagram is presented as projections of solidus and liquidus surfaces and a vertical section at 7.5 at.% B. __________ Translated from Poroshkovaya Metallurgiya, Vol. 46, No. 3–4 (454), pp. 62–71, 2007.     

Al-Zn(Cu)合金的相变和Al-Zn-Cu系相图

Al-Zn-Cusystemistheimportantbasisfor practicalAlalloysandZnalloys[1].Amiscibility gapofthefccphaseexistsabove277℃inthe Al Znsystem[2].Thealloywhosecompositionis atthetopofthemiscibilitygapiscalledsym metricalalloyAlZn.Thisalloyhasmanytypical properties.Theimportantoneisthatthespi nodaldecompositioneasilytakesplaceinit.In ordertoavoidthedecomposition,Cuhasbeen added,whichiseffective.Additionof2%Cu molefractioncoulddelaythespinodaldecompo sitionfortwogrades[3,4].AlZn 2Cuisanalloy which…     

Effect of niobium on glass-formation ability and soft magnetic properties of Gd-doping glassy alloys

The effect of niobium on glass-formation ability and soft magnetic properties were studied in Fe-Gd-B glassy alloys. The glassy alloys exhibited high glass-formation ability when the element of Nb was added. Bulk glassy rod （Fe0.87Co0.13）68.5Gd3.5Nb3B25 with a diameter up to 3 mm was produced by copper mold casting. The size of the atom might play an important role in increasing glass-formation ability. The coercive force of glassy （Fe0.87Co0.13）71.5.xGd3.sNbxB25 （x=1.2, 1.5, 2, 2.5, 3, 4） alloys decreased after the addition of niobium element and was in the range of 1.5-2.9 A/m. The permeability spectrum of （Fe0.87Co0.13）70.3Gd3.5Nb1.5B25 glassy ribbon showed that the relaxation frequency （f0） was 6.1 MHz.     

磁场退火对Fe80Si9B11非晶合金的磁致伸缩特性影响

摘要：利用激光多普勒法测量50Hz下非晶合金带材的磁致伸缩曲线,研究了磁场退火对Fe80Si9B11非晶合金带材的磁致伸缩特性的影响。结果显示,在相同的磁场强度下非晶带材经横磁退火后磁致伸缩最大,无磁场退火次之,纵磁退火时最小。然后,采用Kerr方法观察了非晶合金带材的磁畴形貌,从微观结构上解释了经不同磁场退火后磁致伸缩大小不同的机理。最后,对无磁场退火、横磁退火和纵磁退火后的Fe80Si9B11铁基非晶合金铁芯进行了噪音测试。结果显示,在相同的频率和磁通密度下,非晶合金铁芯经横磁退火后噪音最大,无磁场退火次之,纵磁退火时噪音最小,与非晶合金带材经不同磁场热处理后磁致伸缩大小的规律一致。为解决非晶合金铁芯在实际应用中的噪音问题提供了参考。     

镁合金电磁铸造的电磁场分析

镁合金是具有优越性能的金属材料，镁合金的加工是目前国内外正在研究的新课题。本文通过计算镁合金电磁铸造过程中镁合金所受磁力的范围和大小，来确定镁合金电磁铸造时所需线圈的搅拌频率，从而达到最佳的搅拌效果。计算结果表明，镁合金的电磁铸造过程由于镁合金的高电阻率而具有明显的特殊性，集肤效应不太明显，工频即可满足搅拌的要求，对即将进行的科研具有理论意义和指导作用。     

Effect of Si on austenite stabilization, martensite morphology, and magnetic properties in Fe-26%Ni-x%Si alloys

The effect of Si on the austenite stabilization, martensite morphology, and magnetic properties in Fe-26%Ni-x%Si (x=3.5, 5, and 6)alloys have been studied by means of transmission electron microscopy (TEM) and M(o)ssbauer spectroscopy techniques. TEM observations reveal that the martensite morphology is closely dependent on the Si content. The volume fraction changes of martensite and austenite phases,the hyperfine magnetic field, and isomer shift values have been determined by M(o)ssbauer spectroscopy. The M(o)ssbauer study reveals that the hyperfme magnetic field, the isomer shift values and the volume fiaction of martensite decrease with increasing Si content.