A thermodynamic description for the B-Nd-Cr system has been developed on the basis of the constituent binaries and critically reviewed ternary experimental data. The published thermodynamic descriptions for the B-Nd and Nd-Cr binaries were directly used and that for the B-Cr binary was optimized in the present study. The invariant reactions of Liquid <-> Bcc1+Bcc2 (1237 K) in the Nd-Cr system, the phase stability of B4CrNd and B6Cr2Nd, the liquidus projection and isothermal section were calculated accordingly based on the currently obtained thermodynamic description and compared with the experimental results. The calculation results are in good agreement with the experimental data. (C) 2018 Elsevier B.V. All rights reserved.

The texture of 1235 aluminum alloy cast rolling sheet after asymmetrical rolling was measured by XRDtexture diffraction method. The influence of the different speeds ratio on the thickness texture uniformity of the 1235 aluminum alloy cast rolling sheet was studied. The results show that: the texture of cast rolling billet in thickness is very uneven, the surface of the cast rolling sheet is mainly rotating cube texture, and the central layer is mainly β oriented line of Cu, Sand Bs texture; asynchronous rolling can effectively reduce the nonuniformity of the thickness texture of 1235 aluminum alloy cast rolling sheet, that is, the surface and central layers are mainly β oriented line texture, between them, the effect is the best when the different speeds ratio is 1.2.

The effect of annealing on texture and microstructure of cold rolled LA91 alloy was investigated. The results show that the cold rolled LA91 alloy starts recrystallization after annealing at 240 ℃ for 60 min. After annealing at 280 ℃ for 60 min, recrystallization finishes completely. The thin α-Mg phase is broken to form many spherical α-Mg phase and the coarser α-Mg phase to form a clear bamboo-like structure. The intensity of cube texture {001} in β-phase of the cold rolled LA91 alloy after annealing decreases first, then increases and finaly stops. The intensity of texture {112} <111>decreases. But the intensity of texture {111} <112> increases.

湖南理工学院机械工程学院始终注重本专业学生工程实践能力和创新精神的培养。利用实验、实习、实训、课程设计、毕业设计等实践教学环节，通过开放实验室，结合“大学生研究性学习和创新性实验计划项目”、“机械创新节”、“工程训练综合能力竞赛”、“机械创新设计竞赛”、“数控仿真加工竞赛”和“数字化设计及仿真”等活动，构建了旨在培养学生工程实践能力和创新精神的实践训练体系，使学生掌握扎实的基础知识和较强的工程应用能力，并具备深厚的自我发展潜力和“能说、会做、敢闯”的素质。

The isothermal section in the Cu-Sn enrich part of the Cu-Sn-Ti ternary system at 823K was determined by using solid-solid-liquid diffusion triple approach. One ternary compound CuSnTi was found, and 12 three-phase fields were detected. The following 10 three-phase regions are well established: CuTi2+CuTi+Sn5Ti6, Sn5Ti6+Sn3Ti2+ CuSnTi, Liquid+Sn3Ti2+CuSnTi, Liquid+CuSnTi+Cu3Sn, CuTi+Cu4Ti3+Sn5Ti6, CuSnTi+Cu4Ti3+Sn5Ti6, CuSnTi+Cu3Sn+Cu41Sn11, CuSnTi+Cu41Sn11+Bcc_a2, CuSnTi+Cu4Ti+Cu, and CuSnTi+Bcc_a2+Cu. Phase relations in the Ti-enrich corner of this system require further investigation.

《中国制造2025》指出,制造业是立国之本、兴国之器、强国之基.作为制造业的重要组成部分,机械制造业的发展离不开机械类领域各类工程技术人才的广泛参与.本文探讨基于工程素质培养的适应当前国际、国内形势的机械类工程人才培养课程教学方面的改革.指出地方本科高校特别是新建高校在课程教学改革中,不仅仅要注重大工程观、扎实的基础知识、工程能力的培养,也要体现工程伦理、道德品质、独立个性的培养.

Room-temperature mechanical properties of Cu50Zr40Ti10–xNix (0≤x≤4, mole fraction, %) bulk metallic glasses (BMG) with aspect ratios in the range of 1:1–2.5:1 and loading rates in the range of 1×10−5–1×10−2 s−1 were systematically investigated by room-temperature uniaxial compression test. In the condition of an aspect ratio of 1:1, the superplasticity can be clearly observed for Cu50Zr40Ti10 BMG when the loading rate is 1×10−4 s−1, while for Cu50Zr40Ti10–xNix (x=1–3, mole fraction, %) BMGs when the loading rate is 1×10−2 s−1. The plastic strain (ɛp), yielding strength (σy) and fracture strength (σf) of the studied Cu-based BMGs significantly depend on the aspect ratio and the loading rate. In addition, the σy of the studied Cu-based BMGs with an aspect ratio of 1:1 is close to the σf of those with the other aspect ratios when the loading rate is 1×10−2 s−1. The mechanism for the mechanical response to the loading rate and the aspect ratio was also discussed.

A group of plastic Zr-Al-Ni-Cu bulk metallic glasses (BMGs) with low Zr content was developed and their thermal and mechanical properties were investigated. The results show that these Zr-based BMGs have a single crystallization event for all heating rates in the studied temperature region. The glass transition temperature Tg decreases with increasing Zr content for all heating rates. There are two melting procedures for the BMGs whose Zr content is less than 52 at %, while three melting procedures for the other Zr-based BMGs. The second melting procedure is split into two melting procedures for Zr52.5Al12.2Ni12.6Cu22.7 and Zr53Al11.6Ni11.7Cu23.7 BMGs, while the first melting procedure is split into two melting procedures for the other BMGs. The activation energy decreases with increasing sensitivity index β for the studied Zr-based BMGs. The plastic strain εp is in the region of 0.2%–19.1% for these Zr-based BMGs. Both yield strength σy and fracture strength σf are smallest for Zr55Al8.9Ni7.3Cu28.8 BMG whose εp is largest among all studied Zr-based BMGs and reaches up to 19.1%. In addition, the mechanism for the large difference of the plasticity among the studied Zr-based BMGs is also discussed.

Effect of network structure on plasticity and fracture mode of Zr–Al–Ni–Cu bulk metallic glasses (BMGs) was investigated. The microstructures of transversal and longitudinal sections were exposed by chemical etching and observed by scanning electron microscopy (SEM). The mechanical properties were examined by room-temperature uniaxial compression test. The results show that both plasticity and fracture mode are significantly affected by the network structure and the alteration occurs when the size of the network structure reaches up to a critical value. When the cell size (dc) of the network structure is ∼s3 μm, Zr-based BMGs characterize in plasticity that decreases with increasing dc. The fracture mode gradually transforms from single 45° shear fracture to double 45° shear fracture and then cleavage fracture with increasing dc. In addition, the mechanisms of the transition of the plasticity and the fracture mode for these Zr-based BMGs are also discussed.

Phase formation, glass forming ability, mechanical and thermal properties of Cu 50 Zr 50− x Al x (0⩽ x ⩽11.0) glass forming alloys were systematically investigated. The results show that Cu 50 Zr 47 Al 3 alloy has the best glass forming ability (GFA), lowest fragility index ( m ) and highest fracture strength. There are B2 CuZr and B19′ CuZr phases for Cu 50 Zr 50− x Al x (0⩽ x ⩽5.0) alloys. B2 CuZr phase disappears and two new phases (Cu 10 Zr 7 and CuZr 2 ) appear when 5.05.0). Cu 50 Zr 50− x Al x (0⩽ x ⩽4.0) alloys are off-eutectic compositions while near-eutectic compositions for Cu 50 Zr 50− x Al x (5.0⩽ x ⩽11.0) alloys. The E g , E x , and E p decrease with increasing sensitive factor ( β ) for the studied Cu-based alloys characterized in the room-temperature brittleness. The dependence of the phase formation and GFA on the Al content is discussed.

Mechanism, condition and characteristics for the formation of the network structure in a group of Zr-Al-Ni-Cu bulk metallic glasses (BMGs) were investigated. The results show that the constituent segregation and/or the symplastic growth would be the mechanisms for the formation of the cell structure in the present Zr-Al-Ni-Cu BMGs. The cell structure can be easily obtained for the glass forming alloys whose compositions locate nearby the eutectic point. The shorter the distance is from the eutectic point, the larger the cell and the thicker the cell wall of the network structure will be. The present investigation would provide useful information for the development of the BMG with the network structure.

An artificial neural network (ANN) model was developed for simulating and predicting critical dimension dc of glass forming alloys. A group of Zr-Al-Ni-Cu and Cu-Zr-Ti-Ni bulk metallic glasses were designed based on the dc and their dc values were predicted by the ANN model. Zr-Al-Ni-Cu and Cu-Zr-Ti-Ni bulk metallic glasses were prepared by injecting into copper mold. The amorphous structures and the determination of the dc of as-cast alloys were ascertained using X-ray diffraction. The results show that the predicted dc values of glass forming alloys are in agreement with the corresponding experimental values. Thus the developed ANN model is reliable and adequate for designing the composition and predicting the dc of glass forming alloy.

The corrosion behavior of Cu50Zr40Ti10 (at. %) in HCl and NaCl solutions was investigated. The corrosion current densities icorr in HCl and NaCl solutions increase with increasing Clconcentration when the Cl- concentration is <0.5 molL-1, then continuously increase in the former and decrease in the latter. The icorr is larger in the latter than in the former when the Clconcentration is <0.5 molL-1, while inversely for in 1 molL-1 Cl- solution. The corrosion potential Ecorr decreases with increasing Cl- concentration in HCl. However, the change of the Ecorr vs. the chloride ion concentration in NaCl solution appears down-up-down.

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Structural and thermal sensitivity of Cu(60−x)Zr(30+x)Ti10 (x=0, 5, and 10 at%) amorphous alloys to the application of tension was investigated. The structural sensitivity to tension decreases with increasing Cu content. The crystallization enthalpy increases with increasing excess free volume. The characteristic temperatures of the tensile samples can surpass those of the as-cast ones under a critical heating rate which differs in the Cu content. The increase of the excess free volume significantly influences the glass transition and crystallization procedures.

Zr-Al-Ni-Cu bulk metallic glasses (BMGs) were developed and their fragility parameters (m) were calculated by Arrhenius and Vogel-Fulcher-Tammann (VFT) equations. The results show that the m values of the Zr-Al-Ni-Cu BMGs derived by Arrhenius equation are in agreement with the corresponding m values derived by VFT equation. These Zr-Al-Ni-Cu BMGs characterize in low m values. The low m values for these BMGs would be due to their network microstructures. In addition, the m values of Zr-Al-Cu-Ni BMGs could be obtained by regulating Zr content. The composition of Zr-Al-Cu-Ni BMGs with the lowest m value would be near 54%Zr (mole fraction) because the m value about 13 of Zr54Al13Cu18Ni15 BMG is the lowest among these Zr-Al-Ni-Cu BMGs developed.

Cu50Zr40Ti10 bulk amorphous alloys were fabricated by hot pressing gas-atomized Cu50Zr40Ti10 amorphous powder under different consolidation conditions without vacuum and inert gas protection. The consolidation conditions of the Cu50Zr40Ti10 amorphous powder were investigated based on an L9(34) orthogonal design. The compression strength and strain limit of the Cu50Zr40Ti10 bulk amorphous alloys can reach up to 1090.4 MPa and 11.9 %, respectively. The consolidation pressure significantly influences the strain limit and compression strength of the compact. But the mechanical properties are not significantly influenced by the consolidation temperature. In addition, the preforming pressure significantly influences not the compression strength but the strain limit. The optimum consolidation condition for the Cu50Zr40Ti10 amorphous powder is first precompacted under the pressure of 150 MPa, and then consolidated under the pressure of 450 MPa and the temperature of 380 °C.

Bulk Cu50Zr40Ti10 amorphous alloy composites reinforced with carbon nanotube (CNT) were successfully fabricated by hot pressing technique. Their density, thermal conductivity, and mechanical properties were systemically investigated. The density and the compression strength of the compacts both decrease with increasing CNT content. The thermal conductivity of the compacts decreases when the CNT content is less than 0.10% or exceeds 0.60% (mass fraction), while increases when the CNT content is in the range of 0.1%–0.6%. The strain limit and the modulus of the compacts are obviously improved when the CNT content is less than 1.0% and then decrease significantly when the CNT content exceeds 1.00%. The optimum CNT addition is less than 0.20% at the comprehensive properties point of view.