The compound GdNiSn has been studied by X-ray powder diffraction technique.The crystal structure and the X-ray diffraction data for this compound at room temperature are reported.The compound GdNiSn is orthorhombic wi...The compound GdNiSn has been studied by X-ray powder diffraction technique.The crystal structure and the X-ray diffraction data for this compound at room temperature are reported.The compound GdNiSn is orthorhombic with lattice parameters a=7.2044(1)A,b=7.6895(6)A,c=4.4772(4)A,space group Pna2_(1) and 4 formula units of GdNiSn in unit cell.The Smith and Snyder figure of index F_(30) for this compound is 35(0.015,59).展开更多
1.IntroductionMedium Mn steel was developed be-cause the wear resistance of Hadfield steel(Mn13)is poor under low or medium im-pact and extrusion abrasion[1-4].In theforegoing investigations[2-4]we found thatwith the ...1.IntroductionMedium Mn steel was developed be-cause the wear resistance of Hadfield steel(Mn13)is poor under low or medium im-pact and extrusion abrasion[1-4].In theforegoing investigations[2-4]we found thatwith the increase of C content,theneedle-like and network carbide in mediumMn steel increased(as shown in Fig.1(a)and(c)).Although its wear resistance was largelyimproved,its impact toughness was greatlydecreased.In order to increase toughness,along-term high temperature heat-treatmentwas needed.But the treatment caused cracks展开更多
The electronic structures of rare earth cluster halides R(R_6X_(12)) and their interstitial compounds R_7X_(12)Z were studied by the DV-X_(?) method (R=Sc,Y,Pr,Gd or Er;X=Cl,Br or I;Z=B,C,N,Fe,Co or Ru).The results sh...The electronic structures of rare earth cluster halides R(R_6X_(12)) and their interstitial compounds R_7X_(12)Z were studied by the DV-X_(?) method (R=Sc,Y,Pr,Gd or Er;X=Cl,Br or I;Z=B,C,N,Fe,Co or Ru).The results show that because f electrons in empty rare earth cluster are screened,their orbitals are more difficult to overlap each other,a deficiency of skeleton orbitals in cluster causing the system to be unstable.They are easily condensed into chain compound R_2X_3 or R_5X_8.If a light atom of main group is embedded into octahedral cluster,bonding orbitals formed from interstitial atom and rare earth cluster strengthen cluster skeleton bond in the system to reach structural stability.If embedded atom belongs to transition metal,bonding orbitals composed of that of interstitial atom and rare earth cluster take the place of original cluster skeleton orbitals to form heteronuclear metal cluster (or double-coordination compound).展开更多
The effects of rare earths(RE)-Mg-Ti compound modification on the structures and properties of high-carbon high speed steel(HSS) were researched.The impact toughness(α_k),the fracture toughness(K_(1c))and threshold o...The effects of rare earths(RE)-Mg-Ti compound modification on the structures and properties of high-carbon high speed steel(HSS) were researched.The impact toughness(α_k),the fracture toughness(K_(1c))and threshold of fatigue crack growth(ΔK_(th))are tested.The thermal fatigue test is done on a self-straining thermal fatigue tester,the wear test is done on a high temperature wear test machine.The results show that the matrix can be refined by the RE-Mg-Ti compound modification,the eutectic carbides are inclined to spheroidicize and are distributed evenly,the morphology and distribution of eutectic carbides are improved by appropriate RE-Mg-Ti complex modification.After RE-Mg-Ti compound modification,a little effects can be found on the strength,hardness and red hardness,but the fracture toughness(K_(1c)) and threshold of fatigue crack growth(△K_(th)) are improved in the meantime,the impact toughness (α_k) is increased by over one time,and the resistance to thermal fatigue and wear resistance at an elevated temperature are remarkably improved.展开更多
By pattern recognition chemical bond parameter method, the formability of NaZn<sub>13</sub> type and BaCd<sub>11</sub> type ternary compounds in RE-M Si （RE=La-Lu, M is any metallic element） ...By pattern recognition chemical bond parameter method, the formability of NaZn<sub>13</sub> type and BaCd<sub>11</sub> type ternary compounds in RE-M Si （RE=La-Lu, M is any metallic element） systems has been investigated. And the existence of unknown ternary compounds is predicted by the pattern recognition method.展开更多
利用TEM、XRD等分析手段研究快速凝固Al Ti La合金中的化合物相的结构,以及高温退火后的结构,分析化合物相的高温稳定性,并提出化合物相的孪晶形核理论.快速凝固Al-Ti-La合金形成细小、圆整、弥散的金属间化合物相,经分析为Al20Ti2(RE)...利用TEM、XRD等分析手段研究快速凝固Al Ti La合金中的化合物相的结构,以及高温退火后的结构,分析化合物相的高温稳定性,并提出化合物相的孪晶形核理论.快速凝固Al-Ti-La合金形成细小、圆整、弥散的金属间化合物相,经分析为Al20Ti2(RE),金刚石立方结构,该化合物相形成孪晶,其孪晶面{111},孪晶方向[112],认为化合物相是以孪晶为晶核从熔体中优先其他化合物相形成并生长.展开更多
The effects of La rich rare earth alloys on structure and mechanical properties of ZL101A alloy in as cast, heat treated and remelted states were investigated. The appropriate quantity of the addition of RE alloys a...The effects of La rich rare earth alloys on structure and mechanical properties of ZL101A alloy in as cast, heat treated and remelted states were investigated. The appropriate quantity of the addition of RE alloys and the reasonable heat treatment parameters for integral casting wheel made by low pressure die casting have been suggested.展开更多
基金Supported by a Grant-in-Aid from the International Centre for Diffraction Data and the Natural Science Foundation of Guangxi Zhuang Autonomous Region。
文摘The compound GdNiSn has been studied by X-ray powder diffraction technique.The crystal structure and the X-ray diffraction data for this compound at room temperature are reported.The compound GdNiSn is orthorhombic with lattice parameters a=7.2044(1)A,b=7.6895(6)A,c=4.4772(4)A,space group Pna2_(1) and 4 formula units of GdNiSn in unit cell.The Smith and Snyder figure of index F_(30) for this compound is 35(0.015,59).
文摘1.IntroductionMedium Mn steel was developed be-cause the wear resistance of Hadfield steel(Mn13)is poor under low or medium im-pact and extrusion abrasion[1-4].In theforegoing investigations[2-4]we found thatwith the increase of C content,theneedle-like and network carbide in mediumMn steel increased(as shown in Fig.1(a)and(c)).Although its wear resistance was largelyimproved,its impact toughness was greatlydecreased.In order to increase toughness,along-term high temperature heat-treatmentwas needed.But the treatment caused cracks
基金The project supported by the National Natural Science Foundation of China
文摘The electronic structures of rare earth cluster halides R(R_6X_(12)) and their interstitial compounds R_7X_(12)Z were studied by the DV-X_(?) method (R=Sc,Y,Pr,Gd or Er;X=Cl,Br or I;Z=B,C,N,Fe,Co or Ru).The results show that because f electrons in empty rare earth cluster are screened,their orbitals are more difficult to overlap each other,a deficiency of skeleton orbitals in cluster causing the system to be unstable.They are easily condensed into chain compound R_2X_3 or R_5X_8.If a light atom of main group is embedded into octahedral cluster,bonding orbitals formed from interstitial atom and rare earth cluster strengthen cluster skeleton bond in the system to reach structural stability.If embedded atom belongs to transition metal,bonding orbitals composed of that of interstitial atom and rare earth cluster take the place of original cluster skeleton orbitals to form heteronuclear metal cluster (or double-coordination compound).
文摘The effects of rare earths(RE)-Mg-Ti compound modification on the structures and properties of high-carbon high speed steel(HSS) were researched.The impact toughness(α_k),the fracture toughness(K_(1c))and threshold of fatigue crack growth(ΔK_(th))are tested.The thermal fatigue test is done on a self-straining thermal fatigue tester,the wear test is done on a high temperature wear test machine.The results show that the matrix can be refined by the RE-Mg-Ti compound modification,the eutectic carbides are inclined to spheroidicize and are distributed evenly,the morphology and distribution of eutectic carbides are improved by appropriate RE-Mg-Ti complex modification.After RE-Mg-Ti compound modification,a little effects can be found on the strength,hardness and red hardness,but the fracture toughness(K_(1c)) and threshold of fatigue crack growth(△K_(th)) are improved in the meantime,the impact toughness (α_k) is increased by over one time,and the resistance to thermal fatigue and wear resistance at an elevated temperature are remarkably improved.
基金Financilly Supported by the National Natural Science Foundation of China
文摘By pattern recognition chemical bond parameter method, the formability of NaZn<sub>13</sub> type and BaCd<sub>11</sub> type ternary compounds in RE-M Si （RE=La-Lu, M is any metallic element） systems has been investigated. And the existence of unknown ternary compounds is predicted by the pattern recognition method.
文摘利用TEM、XRD等分析手段研究快速凝固Al Ti La合金中的化合物相的结构,以及高温退火后的结构,分析化合物相的高温稳定性,并提出化合物相的孪晶形核理论.快速凝固Al-Ti-La合金形成细小、圆整、弥散的金属间化合物相,经分析为Al20Ti2(RE),金刚石立方结构,该化合物相形成孪晶,其孪晶面{111},孪晶方向[112],认为化合物相是以孪晶为晶核从熔体中优先其他化合物相形成并生长.
文摘The effects of La rich rare earth alloys on structure and mechanical properties of ZL101A alloy in as cast, heat treated and remelted states were investigated. The appropriate quantity of the addition of RE alloys and the reasonable heat treatment parameters for integral casting wheel made by low pressure die casting have been suggested.
