Carbide refinement in M42 high speed steel by rare earth metals and spheroidizing treatment

The influence of rare earth metals and heat treatment on the microstructure and performance of M42 steel has been investigated by means of an optical microscope OM scanning electron microscope SEM energy dispersive spectroscopy EDS transmission electron microscope TEM electron back-scatter diffraction EBSD and X-ray diffraction XRD . The results show that M2 C is the prevailing type of eutectic carbides in M42 steel. After modification with rare earth metals M2 C eutectic carbides change from the ordered lamellar structure into a circular structure.Despite different morphologies the two carbides present the same characteristics of microstructure and growth orientation.Compared with lamellar carbides M2 C carbides with the circular structure are much easier to decompose and spheroidize after heating which remarkably refines the carbide dimensions.The refined carbides improve the supersaturation of alloying elements in martensite and increase the hardness of M42 steel by 1.5 HRC.

Analysis of Different Rare Metals, and Rare Earth Metals in Harvested Rain Water in Gaza Strip/Palestine by ICP/MS-Data and Health Aspects

This rain water samples harvested for drinking and agriculture from Gaza collected in November 2012 were analyzed for different rare metals (Rb, Zr, Ti, Tl, Sb, Sc, Y), and rare earth metals (La, and Ce). These metals usually have no maximum acceptable limits as there is no sufficient data about their toxicity to human health. Their control should be therefore controlled in water to monitor their concentration in water (ground, harvested, etc.). This study was conducted to determine the water quality of harvested water which is used for drinking in the study area. 43 water samples were collected in November 2012 during the first rain from house wells and rain water pools. The concentrations of the metals detected in the collected harvested rainwater vary significantly between the 43 samples, and all of them were detected in all water samples analyzed in this study. The results obtained from this study suggest a possible risk to the population of the study area given the high concentration of some metals that have no maximum allowed concentration, and the fact that for many people in the study area, harvested rain water is a main source of their water supply.

ABSTRACT From Rare Metals

Effects of Er on the microstructure and properties of AZ31 magnesium alloy prepared via the EMS process,Fabrication of ZnO-based thick film varistors with high potential gradient,Microstructure and mechanical properties of forged Al-7.1Zn-1.1Mg-1.6Cu-0.14Zr alloy after two-step ageing treatment at 120 and 170℃

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Facile and green route to highly luminescent ZnS-shelled CdSe nanocrystals YE Xinyu, ZHUANG Weidong, HU Yunsheng, LUO Xinyu, ZHAO Chunlei, and HUANG Xiaowei Abstract： Highly luminescent CdSe/ZnS nanocrystals were obtained by adapting non-TOP-based synthesis and a subsequent two-phase ZnS shelling procedure： the core CdSe nanocrystals were synthesized in sole solvent paraffin liquid with cadmium oxide, elemental selenium, and oleic acid; the deposition of the ZnS shell was conducted by using zinc stearate in toluene and sodium sulfide in deionized water.

ABSTRACT——From Rare Metals

Optical and acoustic phonon modes confined in gallium phosphide nanoparticles

ABSTRACT——From Rare Metals

Silver sulfide leaching with a copper-thiosulfate solution in the absence of ammonia CUI Yiqi, TONG Xiong, and Alejandro Lopez-Valdivieso Abstract： Leaching from silver sulfide using a copper-thiosulfate solution in the absence of ammonia was investigated.

ABSTRACT——From Rare Metals

The effects of ZnO-B2O3 （ZB2） on the sintering behavior and microwave dielectric properties of （Ca0.254Li0.19Sm0.14）TiO3 ceramics were investigated. The densities of the specimens reached the maximum value by adding 3 wt.% ZB2 and then decreased. The sintering temperature of the specimens was lowered from 1300 to 1100℃ without degradation of the microwave dielectric properties.

RARE METALS

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EFFECTS OF RARE EARTH METALS ON MICROSTRUCTURAL TRANSFORMATION OF LOW OR MEDIUM CARBON Si-Mn-V STEELS DURING QUENCHING AND TEMPERING

The microstruetural transformation of steels:20SiMn2V,20SiMn2VRE,40SiMn2V and 40SiMn2VRE during quenching and tempering have been examined by TEM,X-ray diffraction and dilatometer.It was shown that the addition of rare earth metals not only can refine the austenite grains of the low or medium carbon steels and packet of lath martensite and lath size,lower the M_s temperature,but can also raise the relative percentage of disloca- tion substructure of martensite in medium carbon steel,but there is little effect on volume frac- tion and thermal stability of retained austenite quenching and tempering structure of low or medium carbon steels.The rare earth metals may remarkably inhibit the decomposition of low carbon martensite during low temperature tempering,retard the precipitation of cementite plates in lath grains and delay the spheroidization of carbides.They may also restrain obvious- ly the precipitation and spheroidization of cementite in medium carbon martensite during high temperature tempering.

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Influence of Sn substitution for Co in RCo2 (R = Gd, Tb, Dy) alloys on the structure and magneto-caloric effect ZHUANG Yinghong, DENG Jianqiu, LI Junqin, ZHAN Yongzhong, ZHU Qiming, and ZHOU Kaiwen Abstract: The phases and the

SELECTED ABSTRACTS OF ARTICLES ON RARE METALS FROM CHINESE PERIODICALS

89 1-01 Investigation of SingleMoFeSCubane-Like Cluster Compounds——Ⅲ.TheConversion of Linear Trinuclear Cluster into SingleCubane Cluster and the Structure ofMoFeS(EtNCS)CHCN Reaction ofFe(DMF)[(FeCl)MoS] and EtNCSNa in DMF re-sults in conversion of the linear trinuclear cluster into thesingle cabane—like cluster,MoFeS(EtNCS),thestructure of which has been determined.The influence ofthe ligand—related redox process and the ligation modeon the conversion reaction and the product are discussed.

SELECTED ABSTRACTS OF ARTICLES ON RARE METALS FROM CHINESE PERIODICALS

93-1-38 Chemical Dispersion of MoOand TiOat Interface of MoO/TiOThe dispersion capacity ofMoOand TiOat the interface of MoO/TiOcal-cined at 500℃ for 5h was studied by XRD and FT-IR dif-ference spectra.There is about one monolayer ofnon-crystalline phase of MoOand TiOat the interface.

SELECTED ABSTRACTS OF ARTICLES ON RARE METALS FROM CHINESE PERIODICALS

CONTENTS1.Extractive Metallurgy(40～43)2.Metal Materials and Technology(30～32)3.Semiconductors(38～40)4.Metal Physics(24～26)5.Chemical Analysis and Physical Testing(38～39)93-1-40 Study of Pt-Ga/AlOCatalysts Ⅱ.Ef-fect of Ga on the Surface Structure and Acidity of the Cata-lysts The effect of Ga on the surface structure of sup-port and the acidity of Pt-Ga/AlOcatalysts was studiedby using EPMA,XRD,IR,physical adsorption,frontaladsorption of basic gases and cumene cracking.The results

SELECTED ABSTRACTS OF ARTICLES ON RARE METALS FROM CHINESE PERIODICALS

CONTENTS1.Extractive Metallurgy(9～16)2.Metal Material and Technology(5～9)3.Semiconductor(9～17)4.Metal Physics(5～8)5.Chemical Analysis and Physical Testing(5～11)92 1-9 Determination of Trace Selenium in High-Puri-ty Copper by Polarographic Catalytic Wave after Enrichmentand Separation with Sulfhydrl-Cotton A novel procedure

ABSTRACTS——From Rare Metals

Flotation of indium-beard marmatite from multi-metallic ore TONG Xiong, SONG Shaoxian, HE Jian, and Alejandro Lopez-Valdivieso Abstract: Flotation of indium-beard marmatite from Dulong multi-metallic ore in Yunnan Province of China was studied to improve the grades and recover

RARE METALS

Excellent Elasticity of Ancient Iron SwordAt the beginning of this year an ancient tomb was excavated in the city Xingping,ShaanxiProvince,while a school was under construction.It is indicated that this tomb belongs to EsternHan Dynasty(25～220A.D.).Archaeologists found in the tomb one iron sword,two iron