New TiC/Co1.5CrFeNi1.5Ti0.5 Cermet with Slow TiC Coarsening During Sintering

New TiC/Co_1.5CrFeNi_1.5Ti_0.5 cermet was developed by exploiting the advantages of the high-entropy alloy (HEA) binder. A much finer grain structure and thus improved hardness–toughness combination were obtained as compared with two traditional binders, Ni and Ni₁₃Mo₇. From the coarsening behavior of TiC grains, the coarsening process of TiC in these three binders is diffusion-controlled. The activation energy of TiC + 20%Co_1.5CrFeNi_1.5Ti_0.5 is the highest and that of TiC + 20%Ni is the lowest. The high activation energy of the Co_1.5CrFeNi_1.5Ti_0.5 binder was attributable to its high content of carbon-strong-binding elements, Cr and Ti, and cooperative diffusion and higher packing density of multiple different-sized atoms. Low diffusion coefficient, low surface energy of TiC grains, and low solubility of Ti in the HEA liquid explain the slow coarsening of TiC grains. This study demonstrates that Co_1.5CrFeNi_1.5Ti_0.5 is an excellent HEA binder for TiC cermets.     

Fe-1.3C-1.5Cr-1.5Al超高碳钢等温淬火组织与性能研究

为获得综合性能良好、在工模具上具有广泛应用前景的超高碳钢,利用SEM、维氏硬度计、拉伸试验机和冲击实验机,在确定Al温度的基础上,对Fe-1.3C-1.5Cr-1.5Al超高碳钢在300℃进行等温淬火,研究了等温时间对组织和性能的影响规律.结果表明,Fe-1.3C-1.5Cr-1.5Al超高碳钢Al温度在810℃左右;在300℃下等温淬火能够获得下贝氏体、残余奥氏体及未溶碳化物复相组织,且随等温淬火时间的延长,下贝氏体体积分数增加、残余奥氏体减少,超高碳钢的硬度增大、韧性降低.Fe-1.3c-1.5Cr-1.5Al超高碳钢在830～850℃×1 h奥氏体化后,经300℃等温淬火2 h,其抗拉强度为1 750 MPa,总伸长率为6.9%,硬度为560 HV,冲击吸附功为4J,能够达到工模具钢室温性能要求.     

Effect of heat treatment on formability in 0.15C−1.5Si−1.5Mn multiphase cold-rolled steel sheet

The effects of volume fraction and the stability of retained austenite on the formability of a 0.15C−1.5Si−1.5Mn (hereafter all in wt.%) TRIP-aided multiphase cold-rolled steel sheet were investigated after various heat treatments. The steel sheets were intercritically annealed at 800°C, and isothermally treated at 400°C and 430°C. Microstructural observation, tensile tests and limiting dome height (LDH) tests were conducted on the heat-treated sheet specimens, and the changes in retained austenite volume fraction as a function of tensile strain were measured using an X-ray diffractometer. The results showed a plausible relationship between formability and retained austenite stability. Although the same amount of retained austenite was obtained after isothermal holding at different temperatures, better formability was obtained in the specimens with the higher stability of retained austenite. If the stability of the retained austenite is high, the strain-induced transformation of retained austenite to martensite can be stably progressed, resulting in a delay of necking to the high strain region and improvement in formability.     

纳米晶Fe72.5Cu1Nb1.5Mo1.5V1Si13.5B9合金的磁性能

报道了新开发的纳米晶Fe725Cu1Nb15Mo15V1Si135B9合金的综合磁性能。新合金的直流起始磁导率和矫顽力水平分别达到13×104和064Am-1。在Bm=03T,f=100kHz和Bm=02T,f=200kHz条件下,铁损分别为578kW·m-3和884kW·m-3,这可与纳米晶Fe735Cu1Nb3Si135B9合金的相比,但比优良的功率MnZn铁氧体H7C4的低得多。在Bmf=(10～40)T·kHz条件下,在f=(20～6000)kHz范围内,描述了铁损、相应幅值磁导率和动态矫顽力的行为     

Al-22Si-1.5Ni-1.5Cu-0.8Fe-0.8Mn合金用P-Ce-Sr复合变质处理

采用L^9（3^4）正交表安排P、Ce和Sr对铝-硅合金进行复合变质处理试验。正交试验表明最佳变质剂配方为w（P）2％（CaH2PO4＋2CaSO4）＋w（Ce）0．3％＋w（Sr）0．3％。方差分析结果表明：P对初晶硅影响较显著，而Ce和Sr对初晶硅无影响；Sr对共晶硅影响显著，P对共晶硅影响较显著，Ce无影响。拉伸断口扫描电镜分析表明所有试样均为韧窝状断口。未变质处理的试样拉伸断口上有许多较粗的初晶硅，容易产生应力集中，使抗拉强度降低。复合变质处理的试样断口中的硅相为均匀细粒状，减少了应力集中；复合变质处理使该合金中硅相细化，使布氏硬度提高50％，硬度可达HB84．9；抗拉强度比未经变质的提高20％．Rm=320N／mm^2。     

熔体快淬La1-xNdxFe11．5Si1．5（x=0，0．3，0.5）化合物磁性能和磁熵变

利用熔体快淬法制备了La1-xNdxFe11．5Si1．5（x=0，0．3，0.5）快淬带。通过X射线衍射和振动样品磁强计测试了回火态（1000℃，5h）La1-xNdxFe11．5Si1．5）快淬带的相组成和磁性能。结果表明：不同成分快淬带回火后均可得到稳定的NaZnl，型化合物。和常规的熔炼法相比，用熔体快淬法通过短时间的回火（1000℃，5h）可以制成具有大磁熵变的NaZn13型的化合物。用Nd替代部分的La后，居里温度略有提高，同时保持有大的磁熵变｜△S｜；并且随着Nd含量的增加，有效制冷温区有变宽的趋势。     

0.2C-1.5Mn-1.5Si相变诱发塑性(TRIP)钢板在烤漆过程中的组织和力学性能变化

本文系统地研究了0.2C-1.5Mn-1.5Si TRIP钢板在烤漆硬化处理过程中组织和力学性能的变化规律.结果表明,在烤漆过程中,TRIP钢板中处于亚稳态的残留奥氏体发生了贝氏体相变,经烤漆处理的TRIP钢板屈服强度提高,表现出一定程度的烤漆硬化性.     

Cu-1.5Ni-0.27Si合金形变热处理

利用力学性能、电学性能测试，金相、电镜观察及电子衍射分析研究了不同形变热处理条件下Cu-1．5Ni-0．27Si合金性能与显微组织的关系。结果表明：该合金经850℃快速热轧淬火后表现为明显的变形组织，无动态再结晶现象，只有极少量的第二相析出。450℃时效4h处理后，其显微硬度达到峰值(HVl58)，相对电导率达44％(IACS)。δ-Ni2Si析出相粒子的平均尺寸约为15nm，间距约为10～30nm，与铜基体存在确定的位向关系：(110)m//(211)ppt，[1l0]m∥[324]ppt。合金经80％的冷轧变形后，σb、σ0.2、显微硬度、延伸率和相对电导率(IACS)分别达578MPa、573MPa、HV173、3％和41．5％。合金的强化机制为Orowan位错绕过机制。     

熔体快淬LaFe11．5Si1．5的巨大磁熵变

采用熔体快淬法制备了LaFe11．5Si1．5化合物。利用X射线衍射和能谱分析测定了熔体快淬带的相组成和元素分布：利用磁性能测试结果计算了磁熵变。结果表明：熔体快淬可以得到元素分布均匀的LaFe11．5Si1．5薄带，其相组成为NaZn13型LaFe11．5Si1．5化合物和大量α-Fe。退火后，快淬带中的α-Fe含量大大降低，得到了近似单相的LaFe11．5Si1．5化合物。由磁性能测试并经计算发现，快淬带经1000℃，6h时效后具有巨大的磁熵变。由此可见，熔体快淬可成为一种制备更廉价的高性能磁致制冷材料的新方法。     

LaFe11．5Si1．5By合金的磁热效应

LaFe11．5Si1．5By（y=0,0．1,0．2,0．3,0．4和0．5）系列合金,通过添加少量的B后,可以明显的缩短退火时间。晶格常数随着B含量的增加而逐渐增大。居里温度随着B的增加分别从183K升高到186K。该系列化合物的热滞很小,B的添加对其热滞几乎没有影响。在外加磁场变化为0～1．5T时,等温磁熵变的最大值从20．0J／kgK（y=O）逐渐下降到10．7J／kgK（y=0．5）。该系列化合物在B含量较低时,处于居里温度（R）之上则存在比较明显的场致变磁转变特性。随着B含量增加到0．5时,场致变磁转变特性明显减弱。     

轧制和热处理对Mg-11Li-3Al-1.5Si-1.5Nd合金组织与力学性能的影响

通过光学显微镜、扫描电镜、能谱分析及力学性能测试等手段,研究轧制和热处理工艺对Mg-11Li-3Al-1.5Si-1.5Nd合金板材组织和力学性能的影响,探讨其析出相在合金中的作用。结果表明,铸态合金经过均匀化处理后,汉字形貌的Mg2Si相溶入基体,其综合性能大幅下降。但在随后的轧制过程中,合金的力学性能得到双重提升。合金板材经过淬火处理后,晶粒非常细小,主要由β-Li基体和沿轧制方向分布的少量颗粒状Mg17Al12相组成,抗拉强度最大可达344.3MPa。而退火处理后,其仍保留轧制态的组织,但随着退火温度的升高,析出的白色α-Mg相逐渐减少,板材的抗拉强度略微下降,而塑性则呈先升后降再升高的趋势,其中220℃×1h退火板材的塑性最好,其伸长率为73.1%。     

添加0.5%铜及贝氏体化对0.2C-1.5Mn-1.5Si形变诱发塑性(TRIP)钢板组织和力学性能的影响

系统研究了添加0.5%铜及贝氏体恒温处理工艺参数对0.2C-1.5Mn-1.5Si TRIP钢板组织及性能的影响规律.结果表明,在450 ℃×3 min常规贝氏体恒温处理工艺条件下,在TRIP钢中加入0.5%铜可以明显提高其残留奥氏体量和抗拉强度,但使总伸长率降低;随着贝氏体化时间的增加,TRIP钢板中贝氏体含量增加,而处于亚稳态的残留奥氏体明显减少.     

ZrV1.5Ni1.5 as electrode material in nickel-metal hydride batteries An in situ scanning tunnelling microscopy investigation

We have investigated the alloy ZrV_1.5Ni_1.5 by means of scanning electron microscopy (SEM) with electron probe X-ray microanalysis (EPMA), X-ray diffraction (XRD), in situ STM (scanning tunnelling microscopy in an electrolyte under controlled electrochemical potential) and electrochemical charge discharge measurements. By means of EPMA we found that the alloy is composed of three different crystallographic phases. The main phase (≈75 vol.%) is ZrV_0.81Ni_1.47, the second phase (≈20 vol.%) is V₉₂Ni₈ and the third (≈5 vol.%) is a ZrNi based phase. Using in situ STM we investigated the different corrosion behaviour of the phases. At a potential of −600 mV versus the Hg/HgO reference electrode we observed the corrosion of the vanadium rich phase while the other two phases passivated.     

Microstructure and properties of Al0.3CrFe1.5MnNi0.5Ti x and Al0.3CrFe1.5MnNi0.5Si x high-entropy alloys

In this article, the microstructure, hardness, and corrosion resistance of the Al0.3CrFe1.5MnNi0.5Tixand Al0.3CrFe1.5MnNi0.5Six(x = 0, 0.2, 0.5, 1.0) high-entropy alloys were investigated via X-ray diffraction(XRD)scanning electron microscopy(SEM), digital display Vickers hardness tester, and electrochemical technique These alloys are mainly composed of BCC solid-solution structure. When adding high content of Ti or Si elemen(x C 0.5), some intermetallic compounds are found in the microstructure, which makes the alloys have a high hardness, high brittleness, and easy cracking. While the alloys with low content of Ti or Si(x = 0.2) have a hardness of HV 420–HV 430, and its hardness increases about 14 %compared with that of Al0.3CrFe1.5MnNi0.5. Electrochemical results in 3.5 % NaCl solution show that the alloying elements Ti and Si have a negative influence on the corrosion resistance of the Al0.3CrFe1.5MnNi0.5alloys.     

Effects of phosphorous addition on mechanical properties and retained austenite stability of 0.15C−1.5Mn−1.5Al TRIP-aided cold rolled steels

The effects of a P addition on the mechanical properties and austenite stability are investigated for 0.15C−1.5Mn−1.5Al TRIP-aided cold-rolled steels containing 0.05 and 0.1 wt.% of P. The strength and retained austenite fraction are increased by an increment of the P content. The strengthening of P-added TRIP-aided steel partially comes from the solid-solution hardening effect of P, and a higher fraction of strain-induced martensite plays an important role as well. The elongation of steel containing 0.1 wt.% P is diminished compared with that containing 0.05 wt.% P. This is attributed to the lower mechanical stability of retained austenite in TRIP-aided steel containing 0.1 wt.% of P, which inhibits persistent work hardening during deformation.     

Oxidation Behavior and Electrical Properties of De-siliconized AISI 430 Alloy with Mn1.5Co1.5O4 Coating for Solid Oxide Fuel Cell Interconnect

Oxidation of Metals - The effect of de-siliconization on the oxidation behavior of AISI 430 stainless steel used for solid oxide fuel cell interconnect application was investigated....     

Pda630/1.5压力机下模座的修复

1　前言Pda63 0 / 1 .5压力机是我公司 1 976年从西德瓦格纳公司 (WAGNER)全套引进的具有世界先进水平的一台闭式双点多工位全自动热锻压设备。其公称锻造压力为 63 0 t(6.3 MN) ,作用是为轴承套圈辗压生产线提供锻造毛坯。下模座是 Pda63 0 / 1 .5压力机最重要的特大型模具之一。因下模座失效无法使用 ,锻造厂曾设计图样外委加工制备了一件下模座。但仅用了一个多月 ,便由于成形工位模腔内 4-M2 0螺孔部分失效以及支承面 G局部打堆 ,而无法继续使用 (见图 1 )。依照下模座 (材质为 65Mn)的服役条件 ,其热处理要求应是 :整体调质或退…     

HYDROGEN STORAGE PROPERTIES OF TiMn_(1.5-x)Cr_x

在40℃及初始氢气压力为4MPa条件下,测定了TiMn_(1.5-x)Cr_x合金的首次吸氢动力学曲线,并在19℃测定了TiMn_(1.5-x)Cr_x-H体系的放氢压力-组成等温线。结果表明,用Cr取代TiMn_(1.5)合金中部分Mn时,缩短孕育期,提高吸氢速率,增加吸氢量,放氢量也有一定增加,改善了合金贮氢性能.