Al—Sc合金高温力学性能研究

对Al-0.35Sc合金中加入不同含量的微量过滤族元素Zr、Ti,采用正交试验法测定了这些含Zr、Ti元素的Al-Sc合金的高温（270℃）力学性能,总结了Zr、Ti加放量、时效制度对Al-Sc性能的影响规律,此外还对高温强化机理进行了分析。     

微量元素对InconelX—750改型合金性能的影响

研究了微量元素对ＩｎｃｏｎｅｌＸ－７５０改型合金高温时效硬度及其变化规律的影响，测试了试验合金５００℃、６００℃、８００℃及９００℃下，经不同时时效后合金显微硬度值的变化。研究表明，微量元素可以延缓合金高温长期使用时的硬度下降，提高合金的高温硬度值，尤其在７００℃以下使用时，向量元素的作用效果更明显。     

Pt—（3～5）Rh—Zr—B合金的高温性能

标题合金加入Ｚｒ，Ｂ后，在１１００￣１２００℃，高温性能优地Ｐｔ－７Ｒｈ合金，Ｚｒ、Ｂ元素在合金中主要起固溶强化作用。就高温强度性质而言，该合金可替代Ｐｔ－７Ｒｈ合金，从而节约２￣３ｗｔ％的Ｒｈ。     

活性元素Y和Ce对Fe—25Cr—40Ni合金高温氧化的影响

用离子背散射和慢正电子束研究了活性元素Y和Ce对Fe-25Cr—40Ni合金在高温初期氧化动力学、氧化膜表层成份和微观缺陷结构的影响,实验结果表明了微量活性元素(≥0.05%)在高温氧化初期显著减少了合金的氧化速率,有效地促进了Cr_2O_3的生长,抑制了Fe和Ni氧化物的形成,改善了氧化膜的微观结构,活性元素结合进入氧化膜并在外层膜中(约几十nm)富集,活性元素Ce抗氧化机理不同于Y,Ce使合金氧化膜的空位缺陷显著降低,主要控制了阳离子沿晶格空位向外扩散,而含Y合金由氧化初期主要控制阳离子沿晶格扩散转变为主要控制阳离子沿晶界向外扩散。     

高温工况下一种耐热耐磨新材料的组织、性能研究

选择高温综合性能好、成本高的ZG40Cr25Ni20作为对比材料,以适量的Mn、Si、N等合金元素代替部分Ni合金研制了一种新型耐热耐磨材料;比较了两种材料热处理后的显微组织,并进行了高温磨料磨损和高温抗氧化性能对比试验;结果表明,新材料中适量的Mn、Si、N等合金元素可代替部分Ni合金促进形成奥氏体组织,且高温磨料磨损抗力和高温抗氧化性能与对比材料接近,在实际工况中代替ZG40Cr25Ni20是切实可行的。     

合金元素对镁合金压铸模具钢高温磨损性能的影响

研究了Co、Mo、W和V元素对新型镁合金压铸模具钢高温磨损性的影响。结果表明,当Co元素添加量为8%时,该模具钢的高温耐磨性最好。基体中添加W元素可大幅提高镁合金压铸模具钢的高温耐磨性,添加Mo和V元素对镁合金压铸模具钢的高温磨损性能影响较小。     

BE—CIP—HIP方法制备的Ti—6Al—4V／TiCp复合材料的高温行为

为获得低成本的颗粒增强复合材料可采用如下制备途径：先混合元素粉末(BE),然后通过冷等静压(CIP) 烧结或热等静压 (HIP)成型。由于陶瓷颗粒增强复合材料具有低密度,低成本以及良好的机械性能等特性,因而适合应用在航空及汽车领域。这些复合材料的一个最令人感兴趣的特点是它们能在相当高的温度下保持良好的机械性能。由于高温下钛基陶瓷复合材料的基体与陶瓷粒子之间不发生有害的反应,它比铝基复合材料更具优势。意大利学者主要研究Ti-6Al-4V/TiCp复合材料的热稳定性及高温机械行为。通过冷等静压、真空烧结和热等静压制备出Ti-6…     

双相高温涂层中氧化物相对元素扩散的影响研究

通过扩散方程的建立及数值分析计算,研究了高温氧化条件下双相高温涂层中氧化物相的含量、分布等对NiAl相中元素扩散过程的影响,并结合实验观察进一步分析了在短路扩散条件下涂层/基体界面处的氧化物聚集层中的氧化物的聚集状态与元素互扩散的关系,同时预测了涂层的失效时间,提出了添加氧化物以抑制内界面处元素扩散的合理涂层结构设计。     

低合金钢中合金元素高温氧化行为研究

对低合金钢进行了900~1 200 ℃高温氧化实验,对钢中Si、Mn、Cu、Cr和Ni等合金元素的高温氧化行为进行了研究。结果表明：高温下Si元素与Cu元素存在明显的富集,Si元素会氧化生成Fe2SiO4,阻碍铁离子在氧化铁皮中的扩散,使钢具有一定的抗氧化性;Cu元素可以改善钢的强度、韧性与耐腐蚀性,但是高温氧化后极易形成“富铜液相”,导致出现“铜脆”现象;在1 200 ℃下,Cr元素和Ni元素也会发生富集,Cr在高温下会在氧化铁皮和基体钢之间形成FeCr2O4,同样具有一定的抗氧化性;Mn的氧化物与Fe的氧化物很相似,两者相应氧化物有很高的互溶度;Ni元素对氧化过程没有较大的影响。     

Fe、Ni元素对2A12铝合金组织和性能的影响

铸造过程中在2A12铝合金中加入Fe、Ni元素,分析了Fe、Ni元素对合金显微组织的影响。将加入和未加入Fe、Ni元素的合金试样置于不同的高温环境中,测量其高温性能,比较分析Fe、Ni元素对2A12铝合金高温性能的影响。结果表明Fe、Ni元素的加入可以提高合金的力学性能和高温性能。     

Al、Si及Y多元合金化对Cr-20Nb合金高温氧化行为的影响

针对软第二相Cr稍微降低Laves相NbCr2合金的1200℃抗氧化性,采用Al、Si及Y多元合金化来提高Cr-20Nb合金的高温抗氧化性能。结果表明,多元合金化的Cr-20Nb合金1100℃及1200℃抗氧化性均好于加入单一合金化的及纯Cr-20Nb合金,并随着Si合金元素含量增加,Cr-20Nb合金的氧化增重变小,抗氧化性变好;SEM结果表明,添加合金元素后,氧化膜与基体的粘附性得到了明显提高。     

耐海水腐蚀铸铁的抗氧化性

探讨HD型铸铁（一种耐海水腐蚀低合金铸铁）高温氧化时能否形成类似保护膜的研究结果表明,HD铸铁在高温下形成的氧化膜与一般铸铁无本质区别,其抗氧化性主要与铸铁中Cr、Al、Si含量有关。     

Cr/Al复合合金化Fe_3 Si基有序合金的制备及其力学性能

采用真空电弧熔炼/退火制备了Cr/Al复合合金化Fe3Si基有序合金。通过XRD、SEM对试样进行表征,同时对其显微硬度、压缩强度及弯曲强度等力学性能进行了综合分析。结果表明,Cr/Al复合合金化Fe3Si基有序合金主相仍为Fe3Si相。元素Al,Cr复合合金化较为明显的改善了Fe3Si基有序合金的脆性。Fe65Si25Cr5Al5的抗压和抗弯强度最高,这是因自身高的有序度而呈现的陶瓷性的高强度低应变量特征。有序合金表现出明显的解理断裂特征,Fe80 Si10 Cr5Al5表现出二次解理的特征,Fe75 Si15 Cr5 Al5和Fe70 Si20 Cr5 Al5在断裂时出现了一些韧性特征的撕裂棱,这应与自身适中的有序度有关。     

DOUBLE GLOW PLASMA SURFACE ALLOYING OF Ti6A14V AND TiAl

1. IntroductionThe Double Glbw Plaama Surface Alloying Technique[l,2l is performed in a vacuumglow discharge chamber where two negatively charged electrodes are equipped. One of thetbo cathodbs is a sputtering target made,of one or more of the desired all…     

Behavior of copper-containing high-entropy alloys in harsh metal-dusting environments

Metal dusting is still an unresolved issue at high temperatures. Currently, two material-related strategies to mitigate metal dusting are described in the literature. On the one hand, highly alloyed materials are used, which contain large amounts of protective oxide-forming elements, such as Cr, Al, and Si. The second mitigation strategy is based on inhibiting the catalytic effect of Fe, Ni, and Co. These elements all strongly catalyze the formation of solid carbon from the gas phase. Combining the catalytic protection of Cu alloying for metal dusting with protection by a classical alumina/chromia barrier is a native feature that high-entropy alloys (HEAs) can offer. In this study, the behavior of different equiatomic HEAs with and without Al and/or Cu are studied when exposed at 620°C in a highly aggressive metal-dusting environment.     

Beitrag zum Problem des Einflusses von Silicium,Stickstoff und Bor auf die Verzunderungsbeständigkeit und Warmfestigkeit austenitischer Chrom/Nickel-Stähle

A contribution to the problem of the influence of Si, N and B on the scaling resistance and high temperature strength of austenitic CrNi steels Laboratory and field rests (up to 5000 hrs in an enamelling stove) into the scaling behaviour of alloyed steels, with a particular view to a possible reduction of the Ni content. From the steels – Cr23Ni18, Cr25Ni20Si2, Cr23Ni13, Cr23Ni13Si2, Cr23Ni13Si2N and Cr23Ni13Si2B – the type Cr25Ni20Si2 has the highest, Cr23Ni13 the lowest oxidation resistance. Addition of Si has a negative effect, in particular on creep resistance at high temperatures, while oxidation resistance is improved. In cases of simultaneous thermal and mechanical loads boron additions are preferable. In cases of alternating temperature changes under mechanical stress alloying with nitrogen appears most promising.     

Comparison of titanium silicide and carbide reinforced in situ synthesized TiAl composites and their mechanical properties

This study explored a synthesizing route involving in situ development of reinforcements of titanium silicides in a series of TiAl-based matrices. The main features of this processing route are: (1) Incorporating a small quantity of mechanically alloyed Ti–Al–Si and Ti–Al–Si–C powders, referred to as precursors, into Ti–Al–X (X stands for Cr, Mn, Nb, or their combination) powder mixtures that act as matrices; and (2) Hot isostatic pressing (HIPing) of the cold compacted mixture at a temperature of 1100 °C for 4 h. A series of composites based on different Ti–Al–X matrix were synthesized. The structural evolution in these composites was characterized by X-ray diffraction (XRD) and scanning electron microscopy (SEM). The mechanical properties and compression tests at room and elevated temperatures (600 °C and 800 °C) have been investigated. In addition, the influence of alloying elements in the matrix has been evaluated from their stress–strain responses.     

DOUBLE GLOW PLASMA SURFACE ALLOYING OF Ti6Al4V AND TiAl

In order to improve the wear resistance of titanium alloy Ti6Al4 V and high temper-ature oxidation resistance of intermetallic compound TiAl, the Double Glow PlasmaSurface Alloying Technique (DG technique) was applied to modify the surface proper-ties ofthese materials. Mo, Nb, Cr, Ni were diffused into the substrate materials toform alloyed layers with different properties. This paper shows the microstructures,microhardnesses, distributions of the alloy elements of the alloyed layers. Wear andhigh temperature oxidation tests were carried out. The test results indicate that thewear resistance of Ti6Al4 V and the high temperature oxidation resistance of TiAl wereimproved significantly.     

Effects of alloying elements on plastic deformation of single crystals of MoSi2

Effects of alloying elements on the compression deformation behavior of single crystals of MoSi₂ have been investigated in the temperature range from room temperature to 1500°C. The alloying elements studied include V, Cr, Nb and Al that form a C40 disilicide with Si and W and Re that form a C11_b disilicide with Si. The addition of Al is found to decrease the yield strength of MoSi₂ at all temperatures while the additions of V, Cr and Nb are found to decrease the yield strength at low temperatures (below 800°C) and to increase the yield strength at high temperatures (above 1300°C). In contrast, the additions of W and Re (C11_b formers) are found to increase the yield strength at all temperatures. Of the ternary elements investigated, Al and Nb seem to be the most effective in improving the low-temperature deformability of MoSi₂ while Re and Nb seem to be the most effective in improving the high-temperature strength, judging from the observed yield strength.     

灰铸铁不同合金化同等强度下的加工性能对比研究

制备了用多元合金添加剂(含RE、Cr、Mn、Si、Fe)合金化和Cu合金化的具有相同抗拉强度的2种灰铸铁,对比研究了2种灰铸铁的加工性能.结果表明,具有同强度的2种灰铸铁的布氏硬度和珠光体基体硬度基本相同,但多元合金添加剂合金化灰铸铁的断面敏感性较小,加工性能好,在切削深度分别为1.5、1.75、2.0mm的条件下,其主切削力比Cu合金化灰铸铁的分别降低了23.0％、55.0％和55.2％.