Fe-W-Co和Fe-W-Co-Ni合金的时效硬化

对ＦｅＷＣｏ和ＦｅＷＣｏＮｉ合金的时效硬化特性进行了研究。结果表明两种合金均具有强的时效硬化能力。ＦｅＷＣｏＮｉ低温硬化速率较ＦｅＷＣｏ高。随着时效温度升高,ＦｅＷＣｏ硬化速率迅速上升。ＦｅＷＣｏ合金６３０℃时效１０ｍｉｎ,硬度从淬火态的４７ＨＲＣ上升到６４ＨＲＣ。淬火组织为具有高位错密度的板条马氏体。时效初期出现调幅结构,产生较大共格应力。５７０℃×２ｈ时效,ＦｅＷＣｏ的析出物比ＦｅＷＣｏＮｉ更为弥散细小。这是ＦｅＷＣｏ合金较ＦｅＷＣｏＮｉ合金有较强时效硬化能力的原因。     

18Ni马氏体时效钢时效机理的研究

采用小角Ｘ射线散射、Ｍｏｓｓｂａｕｅｒ谱、透射电镜等方法研究了１８Ｎｉ马氏体时效钢的时效过程。结果表明，１８Ｎｉ合金在固溶处理后５００℃等温时效过程中，首先发生调幅分解，然后在调幅组织的Ｎｉ－Ｍｏ－Ｔｉ富集区以原位形核方式析出含Ｆｅ的Ｎｉ３（Ｍｏ、Ｔｉ）型金属间化合物，随时效时间延长，Ｎｉ３Ｍｏ和Ｎｉ３Ｔｉ粒子聚集长大并部分溶解，同时析出球形Ｆｅ２Ｍｏ金属间化合物，并形成逆转变奥氏体。     

铁基合金激光熔覆组织及高温时效转变的TEM研究

利用ＡＴＥＭ研究了铁基多元合金ＦｅＣｒＷＮｉＣ激光熔覆层的微观组织、亚稳相结构特征以及高温时效时的亚稳相转变机制。结果表明组织为亚共晶组织,即γ＋（γ＋Ｍ７Ｃ３）,γ奥氏体为具有较高合金度的过饱和亚稳相,Ｍ７Ｃ３（Ｍ为Ｃｒ,Ｆｅ,Ｗ）为六方结构的Ｃｒ基亚稳合金碳化物。熔覆组织在高温时效时存在两类碳化物形成机制,即亚稳γ中析出Ｍ２３Ｃ６、Ｍ２Ｃ与ＭＣ碳化物以及Ｍ７Ｃ３→Ｍ２３Ｃ６与Ｍ７Ｃ３→Ｍ６Ｃ的碳化物原位转变机制。熔覆组织具有较高的显微硬度并存在显著的二次硬化特征     

电沉积Ni-Mo和Ni-Mo-P合金的热力学分析

利用热力学数据计算并绘制了ＮｉＰＨ２Ｏ系电位—ｐＨ图,根据电位—ｐＨ图分析了电沉积ＮｉＭｏ和ＮｉＭｏＰ合金镀层的电化学行为;利用Ｘ射线衍射测试了ＮｉＭｏ和ＮｉＭｏＰ镀层在镀态下的物相组成。热力学分析表明：Ｍｏ和Ｐ都难以单金属的形式沉积,它们必须和其它金属以诱导共沉积的方式才能沉积出来;Ｐ,Ｎｉ能以金属间化合物Ｎｉ３Ｐ的形式在阴极上沉积;Ｍｏ以两种形式进入阴极,一种为以ＭｏＯ３固体颗粒复合电镀进入镀层,另一种为以金属间化合物的形态沉积。Ｘ射线衍射分析表明,Ｐ以Ｎｉ３Ｐ,Ｍｏ以ＭｏＯ３与ＭｏＣ的形式存在于镀层中,这一结果与热力学分析结论相一致。     

WC—8（Fe／Ni／Co）R硬质合金的研究

用Ｆｅ、Ｎｉ部分取代ＷＣ－８Ｃｏ合金（牌号ＹＧ８）中的粘结剂Ｃｏ,再添加微量稀土Ｒ制得ＷＣ－８（Ｆｅ／Ｎｉ／Ｃｏ）Ｒ硬质合金,测试了其物理机械性能,研究了粘结剂各种成份比例及烧结温度对硬质合金的影响。结果表明：ＷＣ－８（Ｆｅ／Ｎｉ／Ｃｏ）Ｒ硬质合金的性能可以达到ＹＧ８的性能标准。利用扫描电镜（ＳＥＭ）及Ｘ射线衍射（ＸＲＤ）对其作了显微结构分析,同时探讨了影响ＷＣ－８（Ｆｅ／Ｎｉ／Ｃｏ）Ｒ合金性能的     

Fe-Co-W-Mo型表面时效硬化合金的表面时效硬化特性(Ⅱ)

利用双层辉光离子渗金属技术在工业纯针表面形成高钴的Ｆｅ－Ｃｏ－Ｗ－Ｍｏ型表面时效硬化合金。研究表明,这种表面合金具有时效硬化迅速、硬化能力强和抗回火退化能力强的特点。合金经１２４０℃固溶处理后５４０℃的时效５ｍｉｎ,硬度就从固溶态的５００ＨＶ０．２左右上升到７５０ＨＶ０．２;时效４０ｍｉｎ,硬度上升到１２００ＨＶ０．２左右;于７００℃回火２小时,表层硬度仍保持７２０ＨＶ０．２以上。     

化学镀Fe—Mo—W—B非晶态合金的晶化

利用化学镀获得非晶态Ｆｅ－Ｍｏ－Ｗ－Ｂ四元合金镀层。用Ｘ射线衍射方法研究了镀层的结构和晶化过程。结果表明;Ｂ含量在９．８ａｔ％－２７．３ａｔ％范围内镀层为非晶态结构,该区域大于Ｆｅ－Ｂ二元合金镀层,但不如Ｆｅ－Ｍｏ－Ｂ三元合金镀层。观察到两步晶化过程：首先析出的晶化相为α－Ｆｅ,Ｆｅ３Ｂ和（Ｍｏ,Ｗ）２Ｂ;然后在较高温度出现Ｆｅ２Ｂ,（Ｍｏ,Ｗ）Ｂ和Ｆｅ（Ｍｏ,Ｗ）的衍射峰。     

不同钒,碳含量高速钢的凝固组织及相组成

利用热分析，Ｘ射线衍射和着色金相法详细研究了Ｆｅ－５Ｃｒ－５Ｍｏ－Ｔ２－Ｖ－Ｃ系合金中Ｖ和以Ｃ量对凝固过程中结晶相的种类和结晶温度的影响，得到了合金万分与凝固组织的关系，建立了（Ｆｅ－５Ｃｒ－５Ｍｏ－５Ｗ－２Ｃ）－Ｖ和（Ｆｅ－５Ｃｒ－５Ｍｏ－５Ｗ－３Ｖ）－Ｃ的准二元相图，以及（Ｆｅ－５Ｃｒ－５Ｍｏ－５Ｗ）－Ｖ－Ｃ合金的液相面投影图。     

异质焊头Cr5Mo/Cr21Ni12碳扩散的研究

利用透射电子显微镜（ＴＥＭ）、能谱仪（ＥＤＸ）和电子探针显微分析仪（ＥＰＭＡ）研究了珠光体钢／奥氏体钢（Ｃｒ５Ｍｏ／Ｃｒ２１Ｎｉ１２）异质焊头在高温儿和长期服役中元素Ｃ,Ｃｒ,Ｎｉ,Ｆｅ的扩散行为。结果表明：时效时奥氏体钢中Ｃｒ,Ｎｉ原子向熔合界面方向扩散,Ｆｅ原子向相反的方向扩散;增碳层中析出碳化物Ｍ２３Ｃ６的成分与时效时间无关;增碳层最高含碳量由析出碳化物的类型、成分及紧靠熔合界面奥氏体钢中的     

宽滞后形状记忆合金丝试制成功

通过Ｍｎ的加入量的变化，探讨了Ｍｎ在Ｗ－Ｎｉ－Ｆｅ－Ｃｏ（Ｍｎ）系重合金中的存在状态及其作用机制。结果表明：Ｍｎ的存在，可使Ｗ－Ｎｉ－Ｆｅ－Ｃｏ系重合金的塑性和韧性得以提高；Ｍｎ在合金中，主要以球形细小颗粒状ｆｃｃ的ＭｎＯ的Ｍｎ３Ｏ４四方晶系的Ｍｎ２Ｏ３，正交、四方及ｂｃｃ的Ｍｎ２Ｏ３，正交晶系的ＭｎＯ２及ｒ－ＭｎＯ２，六角晶系的δ－ＭｎＯ２和ｆｃｃ的ａ－ＭｎＳ之状态弥散分布于粘结相中，且部分固溶     

PLASMA SURFACE ALLOYING OF AGE HIGH SPEED STEEL

１．ＩｎｔｒｏｄｕｃｔｉｏｎＣｏ２３Ｗ１１Ｍｏ７,ａｇｅｉｎｇｈｉｇｈｓｐｅｅｄｓｔｅｅｌ（ＡＨＳＳ）ｗｉｔｈｈｉｇｈｃｏｂａｌｔ,ｉｓｏｆａｓｔｒｏｎｇａｂｉｌｉｔｙｏｆａｇｅｈａｒｄｅｎｉｎｇ,６８９～６９ＨＲＣａｆｔｅｒａｇｅｉｎｇ,ａｈｉｇｈａｎｔｉｔｅｍｐｅｒｓｏｆｔｅｎｉｎｇ,６０～６１ＨＲＣａｆｔｅｒｔｅｍｐｅｒｉｎｇａｔ７００℃ｆｏｒ４ｈ,ａｎｄｈｉｇｈｈｉｇｈｔｅｍｐｅｒａｔｕｒｅｈａｒｄｎｅｓｓ,１００ＨｖｍｏｒｅｔｈａｎｔｈａｔｏｆＭ４２ａｔ６００℃ａｎｄ６５０℃…     

新型高强高韧钢G99的超精细场研究

用Ｍｏｅｓｓｂａｕｅｒ谱学对新型高强度韧钢Ｇ９９在不同温度回火后的超精细场变化进行了研究。用透射电镜和电子衍射分析了合金碳化物的析出。结果表明,Ｇ９９钢中超精细场分布、碳化物和奥氏体量都随着回火温度和升高而变化,主要是由于在回火过程中回火马氏体内Ｆｅ－Ｃｏ,Ｆｅ－Ｎｉ近邻增多,Ｆｅ－Ｃｒ,Ｆｅ－Ｍｏ近邻减少,渗碳体的溶解与合金碳化物的析出以及残余奥氏体转变与逆转奥氏体的产生所致。合金碳化物的弥散     

W, Mo, Co Co-diffusion on Steel with Different Carbon Content

AGE-HARDENED HIGH SPEED STEEL has veryhigh hardness,high-temperature hardness,anti-tempersoftening ability and is thought as an ideal cut toolmaterial for difficult machining materials such as nickelalloys and titanium alloys[1].However,because thesteel contains much cobalt,it has very high cost[2].Inorder to reduce the steel cost,a surface age-hardenedhigh-speed steel has been formed by diffusing W,Mo,Co into the surface of ingot[3].It is an advancedgradient material,both the age-h…     

镀附钛、钼、钨金刚石与铜基合金结合剂工具的结构性能研究

为了实现金刚石与金属结合剂间的冶金结合,本文用镀Ti、Mo、W的金刚石与含Ni、Co的铜基合金结合剂制成了刀头,通过切割试验和抗折试验,研究了其强度特征和切割性能,并用X射线、扫描电镜和能谱分析对镀层和金刚石、结合剂之间的作用进行了微观分析。结果表明:Ti、Mo、W镀层一方面与金刚石发生界面化学反应形成相应的碳化物,另一方面又与金属结合剂形成化学键合并部分溶入结合剂液相中。这样,由Ti、Mo、W镀层的中介作用实现了铜基金属结合剂与金刚石之间的冶金结合,使金刚石工具的性能大幅度提高。     

FeWMoCo时效硬化合金的表面冶金工艺（Ⅰ）

利用双层辉光离子渗金属技术可在工业纯铁表面形成铁、钨、钼、钴时效合金。研究了形成这种合金的表面冶金工艺和渗层组织状态、渗层成分分布以及渗金属工艺参数改变对渗层厚度及渗层成分分布的影响。结果表明， 表层Ｗ， Ｍｏ ， Ｃｏ 含量可达到高Ｃｏ 时效合金Ｗ１１ Ｍｏ７Ｃｏ２３ 的水平， Ｃｏ 含量为１８ ％ ～３０ ％ ， Ｗ 含量为７ ％ ～１７ ％ ， Ｍｏ 含量为５ ％ ～９ ％ 。     

热处理对12Ni无钴马氏体时效钢微观组织和性能的影响

研究了高温固溶和时效热处理对12Ni无钴马氏体时效钢微观组织和性能的影响。结果表明:在原始固溶态试样中存在粒状和长粒状析出相,经能谱分析为Fe(Mo,Ti)或Fe2Ti型金属间化合物,消耗了大量的强化元素Mo,导致合金时效处理后强度不足(1100MPa);高温固溶处理后消除了粗大析出相,获得单一的板条马氏体组织;进一步改进时效热处理工艺,合金组织呈现弥散分布的纳米尺度的Ni3Mo、Ni3Ti强化相,使合金强度显著提高,达到1225MPa。     

金属间化合物对高温合金强化机理的研究

研究了金属间化合物对高温合金材料的强化作用,在CrWMoV合金中添加Al和Ni可以形成Ni-Al,Fe-Al和W－Al系等金属间化合物,在合金中起到弥散强化作用和抗氧化作用,能提高合金的高温强度和冲击韧性,实验发现以2％Al的添加为最佳。     

Nickel-Based Single-Crystal Superalloys (Ni,Co)-Al-(Ta,Ti)-(Cr,Mo, W) Designed by Cluster-Plus-Glue-Atom Model and Their 1000 h Long-Term Ageing Behavior at 900 degrees CEI北大核心CSCD

It has been pointed out recently that the compositions of industrial alloys are originated from cluster-plus-glue-atom structure units in solid solutions. Specifically for nickel-based superalloys, after properly grouping the alloying elements into Al, Ni-like ((Ni) over bar, including Ni, Co, Fe, Re, Ru and Ir), gamma '- forming Cr-like ((Cr) over bar (gamma '), including Ta, Ti, V, Nb), and gamma-forming Cr-like ((Cr) over bar;(gamma), including Cr, Mo and W), the optimal formula for single-crystal superalloys has been established [Al-(Ni) over bar (12)] (Al-1(Cr) over bar (gamma ')(0.5)(Cr) over bar (gamma)(1.5)). In this work, the first generation single-crystal superalloys were investigated on the basis of the proposed formula, by using (Ni) over bar=(Ni and Co), (Cr) over bar (gamma ')=(Ta and Ti), and (Cr) over bar (gamma)=(Cr, Mo and W). Two series of alloys were designed, formulated respectively as group A: [Al-Ni11Co1] (Al1TaxTi0.5-xCr1W0.25Mo0.25), with x=0, 0.25 and 0.5 (the corresponding mass fractions of Ta and Ti are respectively 0Ta-2.65Ti, 4.82Ta-1.26Ti and 9,32Ta-0Ti), and group B: [Al-Ni12-yCo gamma](Al1Ta0.25Ti0.25Cr1W0.25MO0.25), with y=1.5, 1.75, 2 and 2.5 (the corresponding mass fractions of Co are respectively 9.43Co, 11Co, 12.57Co and 15.71Co). The single-crystal superalloys were prepared using selector technique. And then they underwent the following tests of incipient melting, standard heat treatment and 1000 h long term ageing at 900 degrees C. It is found that: (1) In group A, with increasing Ta content (decreasing Ti), all the incipient melting temperatures are increased to above 1330 degrees C, and to the highest value is between 1335 degrees C and 1340 degrees C for alloy 9.32Ta-0Ti; the gamma(')gamma(') lattice negative misfits after standard heat treatment are reduced from -0.262% (0Ta-2.65Ti) to -0.247% (9.32Ta-0Ti); the gamma(') coarsening tendency after long-term ageing is deduced, and alloy 9.32Ta-0Ti has the lowest coarsening rate (K=5.6x10(-5) mu(3)/h). (2) In group B, the Co content does not influence the incipient melting temperature (always above 1330 degrees C) and the coarsening rate of gamma(') after long-term ageing. The major role of Co is to increase the mean size of the gamma(') precipitates to about 0.55 pm and the gamma(') volume fraction to about 69% after the standard heat treatment. These two groups of alloys have their gamma(') coarsening rates approaching the level of third-generation single-crystal superalloys (K approximate to(2.08 similar to 3.82)*10(-5) mu m(3)/h).     

合金元素对新型Co-Al-W合金热腐蚀行为的影响

研究了由γ'-Co₃(Al,W)相沉淀强化的新型钴基Co-Al-W 高温合金在800℃、75% Na₂SO₄+25% NaCl熔盐中的热腐蚀动力学及合金元素Mo、Nb、Ta和Ti对合金热腐蚀行为的影响。研究发现,2Mo、2Nb、 2Ta和2Ti合金比9.8W合金具有更好的抗热腐蚀能力,Mo和Ti对提高合金耐热腐蚀能力的效果比Ta和Nb显著。加入合金元素的合金热腐蚀膜由三层组成,即主要由Co氧化物CoO和Co₃O₄组成的腐蚀膜外层,由合金元素、Al、 Co及W复杂氧化物组成的中间过渡层和由Al、Co氧化物组成的腐蚀膜内层。随着腐蚀时间的增加,中间过渡层厚度逐渐增加,热腐蚀膜内、外层厚度变化不大,但内层致密性逐渐增加。     

First principles study of site substitution of ternary elements in NiAl

Site substitution of ternary elements in ordered compounds influences the electronic structure and hence the properties of compounds at the continuous level. The electronic structure and binding energy of a number of NiAl-X alloy systems (X=Ti, V, Cr, Mn, Fe, Co, Zr, Nb, Mo, Hf, Ta, W, Si, Ga, or Ge) were calculated using the discrete variational cluster method based on the local density approximation of the density functional theory. The site preference of the ternary additions to NiAl was investigated by employing the Bragg–Williams model to analyse the calculated binding energy. The results show that all the considered ternary elements possess stronger preference to the Al sublattice sites than a Ni atom does. A new method of identifying sublattice substitution of ternary additions in NiAl was proposed by comparison of the binding energies per atom of the ternary and the binary clusters involving the fourth nearest neighbours. The analysis suggests that Fe and Co atoms occupy the Ni sublattice sites, whereas Si, Ga and Ti atoms occupy the Al sublattice sites. The remaining elements may substitute for both sublattices: Mn is most likely to go for the Ni sublattice; V, Cr, Zr, Nb, Mo, Hf, Ta, W and Ge have a larger preference for the Al sublattice, but Cr and W do not show significant preference to any sublattice. The densities of states involving alloying additions of Co, Si and Cr were further investigated to clarify the site preference of the alloying additions.