Cr含量对Er2Fe17-xCrx合金相结构与微波吸收性能的影响

采用非自耗电弧熔炼炉制备了Er₂Fe_17-xCr_x(x=0、1、2、3、4)合金,借助X射线衍射仪（XRD）、扫描电镜（SEM）和网络矢量分析仪（VNA）研究了Cr的加入量对Er₂Fe₁₇合金相结构及微波吸波性能的影响。结果表明,x=0、1、2时,合金主要由单相Er₂Fe₁₇组成;继续增加Cr的含量,当x=3、4时,合金由Er₂Fe₁₇和Er₆Fe₂₃两相组成。当吸波涂层厚度d=2 mm时,Er₂Fe_17-xCr_x（x=0、1、2、3、4）合金的最小吸收峰值在9、13、14.5、15.8和16.8 GHz处分别达到－17.5、－20、－39.2、－17和－15 dB;吸收峰频率随着Cr含量的增加,向高频方向移动。随着吸波涂层厚度的增加,Er₂Fe₁₄Cr₃试样的吸收峰频率向低频方向移动,吸收峰值先减小后增大,最佳匹配条件出现在d=2 mm处。     

退火温度对FeMoCrVTiSix高熵合金组织及力学性能的影响

在400、600、800、1100 ℃下对FeMoCrVTiSi_x(x=0、0.3)进行退火处理,利用X射线衍射仪、扫描电镜、差热扫描分析仪、显微硬度计、万能试验机等探究了不同退火温度对合金的组织和力学性能的影响。结果表明,Si元素的添加提高了FeMoCrVTi高熵合金的热稳定性。经过退火处理,FeMoCrVTiSi_x高熵合金的微观组织仍为以BCC固溶相为主的枝晶结构,但在枝晶边缘出现黑色的细小富Ti相,其含量随着退火温度的增加而增多,在1100 ℃下富Ti相回溶。富Ti相的析出提高了合金的硬度,其中,800 ℃退火后试样的硬度达到最大值,FeMoCrVTi试样的硬度达到932 HV0.2,FeMoCrVTiSi_0.3的硬度达到998 HV0.2。     

激光熔覆AlxNbMn2FeMoTi0.5高熵合金涂层的组织与性能

使用激光熔覆技术在Q235钢基体上制备Al_xNbMn₂FeMoTi_0.5高熵合金涂层,期望借此提高干切削技术适用刀具表层的硬度和耐磨性。经过初步筛选之后,主要研究了Al_xNbMn₂FeMoTi_0.5(x=1、1.5、2)高熵合金涂层体系,并采用XRD和3D激光扫描成像等手段分析了不同Al含量的Al_xNbMn₂FeMoTi_0.5合金涂层的晶相结构、显微组织和具体元素分布。结果显示,对于Al_xNbMn₂FeMoTi_0.5高熵合金涂层,随着Al含量的增加,涂层的相结构由单一的BCC相逐渐转变为双相BCC结构,晶粒逐渐细化。当x=2时,Al_xNbMn₂FeMoTi_0.5高熵合金涂层硬度最高,平均为1089.6 HV0.3,大约为基材的5倍,且其具有最优的耐磨损性能。x=1.5时,Al_xNbMn₂FeMoTi_0.5高熵合金涂层的自腐蚀电位最高,自腐蚀电流密度最小,耐腐蚀性最好。     

硼对铸态Al0.3CoCrFeNi高熵合金组织及性能的影响

采用冷坩埚悬浮熔炼法制备了Al_0.3CoCrFeNiB_x(x=0,0.01,0.05,0.1)系列高熵合金。利用X射线衍射仪、电子背散射衍射分析、扫描电子显微镜及附带的波谱仪分析了B的添加对Al_0.3CoCrFeNi合金组织结构的影响,研究了Al_0.3CoCrFeNiB_x合金的显微硬度、室温摩擦磨损性能及室温压缩性能。结果表明:Al_0.3CoCrFeNi合金为fcc结构,随着B含量的增加,fcc相基体中晶界处Cr₂B析出相逐渐增多,且Cr₂B相由颗粒状分布逐渐转变为连续网状分布,致使合金的硬度、耐磨性和屈服强度均逐渐提高。可见,Cr₂B析出相弥散强化作用显著,Al_0.3CoCrFeNiB_0.1综合性能更佳。     

热处理对Y2O3掺杂WC-Co硬质合金显微组织及性能的影响

采用固液掺杂法和放电等离子烧结制备了WC-Co-Y₂O₃硬质合金，随后对其进行了不同温度的退火处理。采用光学显微镜、X射线衍射仪(XRD)、扫描电镜(SEM)和维氏硬度计等研究了热处理前后WC-Co-Y₂O₃硬质合金的显微组织和力学性能。结果表明：氧化钇的加入可以细化WC-Co-Y₂O₃合金中的WC晶粒，提高了合金的维氏硬度和断裂韧性；随着退火温度的升高，WC-Co-Y₂O₃合金的维氏硬度逐渐降低，断裂韧性先升高后降低；WC-Co-Y₂O₃合金在500℃退火时拥有最佳的综合性能，维氏硬度为(1377±15) HV30,断裂韧性为(13.0±0.4) MPa·m^1/2。     

预氧化处理对MP35N合金高温氧化行为的影响

目的 探索并优化合金成分、工艺以获得致密稳定的预氧化膜,提高合金抗氧化能力。方法 利用非自耗真空电弧炉熔炼合金,在真空容器中加热金属及其氧化物粉末获得平衡氧压。通过莱茵装置进行预氧化实验。通过FactSage计算Co-Ni-Cr-Mo-Al-Si体系的合金组织相图及其氧化相图,利用X射线衍射(XRD)和扫描电子显微镜对预氧化的试样进行物相分析。结果 在1000℃、10^–17atm氧压下预氧化,未含Si的MP35N合金表面出现Cr₂O₃氧化物;随着Si添加量的增加,表面氧化物变为(Al,Cr)₂O₃,以Cr₂O₃为主,内氧化物为Al₂O₃;当Si含量(质量分数)为3%时,内部形成了近乎连续的带状Al₂O₃氧化膜。在1 000℃、10^–25 atm氧压下,合金表面形成连续的Al₂O₃膜;...     

Mn含量对Zn-Al-Mg合金组织和耐腐蚀性能的影响

为了使热镀锌产品获得更好的耐腐蚀性能,通过感应熔炼制备了3种不同Mn含量的Zn-Al-Mg合金铸锭,分别为Zn1Al1Mg0.5Mn、Zn1Al1Mg1.2Mn、Zn1Al1Mg2.5Mn,并分析了其凝固组织和腐蚀行为。结果表明：通过相图计算预测了含Mn的Zn-Al-Mg合金中Al-Mn化合物类型为Al₁₁Mn₄、Al₈Mn₅、Al_0.8Mn; Zn1Al1Mg0.5Mn、Zn1Al1Mg1.2Mn合金的Al-Mn析出相分别为Al₁₁Mn₄、Al₈Mn₅,随着Mn含量的增加,Zn1Al1Mg2.5Mn合金中的Al-Mn析出相为Al₈Mn₅和Al_0.8Mn,其中Al₁₁Mn₄和Al₈Mn₅相主要在共晶组织中析出,Al_0.8     

Si含量对WMoNbCrTi高熵合金微观组织和力学性能的影响

WMoNbCrTi高熵合金是一种极具应用潜力的高温结构材料，添加Si有望提高其综合力学性能。以高能球磨粉末为原料，采用放电等离子烧结技术制备了WMoNbCrTiSi_x(x=0、0.1、0.25和0.5)高熵合金，研究Si含量对其微观组织和力学性能的影响。结果表明：加入Si后高熵合金的组织由BCC固溶体、Laves相和硅化物组成。当x=0.1时，Si主要形成Ti₅Si₃,当x=0.25时，大部分Si与Ti形成Ti₅Si₃,少部分Si与Nb形成Nb₃Si,当x=0.5时，Si主要形成Ti₅Si₃、Nb₃Si和Cr₃Si。当x从0增加到0.5时，WMoNbCrTiSi_x高熵合金的硬度由9.84 GPa增加到13.46 GPa,断裂韧性从6.68 MPa·m^1/2下降到4.72 MPa·m^1/2。WMoNbCrT...     

Tix(AlNbZr)100-x系多主元合金力学性能的第一性原理研究

通过对合金的固溶体参数以及相比例图进行计算,研究了Ti_x(AlNbZr)_100-x系多主元合金的固溶体相形成规律,运用基于密度泛函理论的第一性原理方法研究了Ti含量变化对Ti_x(AlNbZr)_100-x系多主元合金结构稳定性以及力学性能的影响。结果表明,Ti_x(AlNbZr)_100-x系多主元合金可以形成稳定的固溶体相,且合金主要由BCC相和Al₃Zr₅相组成,随Ti含量增加,合金的液相线降低,Al₃Zr₅相的相形成温度减小,直到Ti含量为60%~70%时,Al₃Zr₅相消失,合金由单一BCC相组成;Ti含量增加可以提高合金的结构稳定性,当Ti含量为25%~70%时,合金具有良好的力学稳定性,合金的体积模量、剪切模量以及杨氏模量随着Ti含量的增加呈上升趋势。Ti_x(AlNbZr)_100-x系多主元合金的基态能量和形成热随着Ti含量的增加而降低,表明增加Ti含量可以增加该合金系的热力学稳定性,使合金更易形成固溶体相。     

铸态Mg-9Gd-1.5Zn-xAl合金的显微组织和力学性能

采用铸造法制备了Mg-9Gd-1.5Zn-xAl(x=0、0.3、0.8和1.3 mass%)合金,通过X射线衍射仪、光学显微镜、扫描电镜等研究了不同Al含量对Mg-9Gd-1.5Zn合金物相和显微组织的影响,并采用电子拉伸试验机测试了室温下4种合金的力学性能。结果表明：铸态Mg-9Gd-1.5Zn合金的组织由α-Mg基体和沿晶界分布的Mg₅Gd和(Mg, Zn)₃Gd相组成,加入Al元素后,合金组织中Mg₅Gd相逐渐减少,并产生了新相Al₂Gd、Al₁₁Gd₃和LPSO(Mg₁₂Gd(Al, Zn))。Al元素促进了有效异质形颗粒(Al₂Gd)的产生,抑制了晶粒长大,合金的组织明显细化,起到了细晶强化的效果。当Al添加量为0.8%时,合金的抗拉强度、屈服强度和伸长率分别为192.2 MPa、154.8 MPa和16.6%,与不含Al的Mg-9Gd-1.5Zn合金相比,分别提升了47.1%、64.8%和121.3...     

Effects of Post-weld Heat Treatment on Microstructure,Mechanical Properties and the Role of Weld Reinforcement in 2219 Aluminum Alloy TIG-Welded Joints

In as-welded state, each region of 2219 aluminum alloy TIG-welded joint shows diff erent microstructure and microhardness due to the diff erent welding heat cycles and the resulting evolution of second phases. After the post-weld heat treatment, both the amount and the size of the eutectic structure or θ phases decreased. Correspondingly, both the Cu content in α-Al matrix and the microhardness increased to a similar level in each region of the joint, and the tensile strength of the entire joint was greatly improved. Post-weld heat treatment played the role of solid solution strengthening and aging strengthening. After the post-weld heat treatment, the weld performance became similar to other regions, but weld reinforcements lost their reinforcing eff ect on the weld and their existence was more of an adverse eff ect. The joint without weld reinforcements after the post-weld heat treatment had the optimal tensile properties, and the specimens randomly crack in the weld zone.     

新型的治疗阿尔茨海默氏症药物(1-二甲基磷酰基-2,2,2-三氯)-乙基-1-醇烟酸醋对体外神经细胞的作用

目的: 观察本实验室合成的一种治疗阿尔茨海默氏症(AD)的药物(1-二甲基磷酰基-2, 2, 2 -三氯)-乙基^-1-醇烟酸醋(NMF),对体外培养的皮层神经细胞活性的影响以及对海人藻酸(KA)所致的神经损伤的保护作用。方法: 采用体外培养皮层神经元的方法,解剖分离 15 d胚胎小鼠皮层神经细胞, 接种于 96孔板,48 h 后加药并培养 72 h,以 MIT 法 观察 NMF 对小鼠皮层神经细胞活性的影响;同时将接种于 24 孔板的细胞预先给予 NMF,d 3 时加或不加KA处理后,以台盼蓝染色鉴别并计数死、活细胞,可得出细胞的存活率。结果: NMF 明显促进胎鼠皮层神经元活性,其中 NMF1、0. 1、10nmol·L^-1促进神经元活性增殖率分别高达 34.7%、37.4%、36. 7%, NMF 明显促进正常胎鼠皮层神经元存活卒,与对照组比较,10nmol·L^-1 NMF 对皮层神经元的存活率分别提高 39.3%、73.5%。 NMF能显著 对抗 KA 所致的神经元损伤,与 KA 损伤组相比, NMF0.1、10、10nmol·L^-1对损伤皮层神经元的保护率分别为 77.30%、80.10%、84.15%。结论: NMF 明 显促进胎鼠皮层神经元的洁性、提高正常皮层神经元,的存活卒,并能有效地保护KA所致的神经元损伤,提示 NMF 是一种很有潜力的治疗 AD 的药物。     

The First Phase of the SRIF Industrialized Base in ＂West Area＂ Has Been Put into Operation

After nearly two years＇ tense construction, the first phase of industrialized base of Shenyang Research Institute of Foundry （SRIF）, located at the Tiexi Casting and Forging Industrial Park in the west of Tiexi District, has now been completed and formally put into operation.     

THERMODYNAMICS STUDY ON THE DECOMPOSITION OF CHROMITE WITH KOH

Institute of Process Engineering, Chinese Academy of Sciences, China, has proposed a method for oxidative leaching of chromite with potassium hydroxide. Understanding the mechanism of chromite decomposition, especially in the potassium hydroxide fusion, is important for the optimization of the operating parameters of the oxidative leaching process. A traditional thermodynamic method is proposed and the thermal decomposition and the reaction decomposition during the oxidative leaching of chromite with KOH and oxygen is discussed, which suggests that chromite is mainly destroyed by reactions with KOH and oxygen. Meanwhile, equilibrium of the main reactions of the above process was calculated at different temperatures and oxygen partial pressures. The stable zones of productions, namely, K2CrO4 and Fe2O3, increase with the decrease of temperature, which indicates that higher temperature is not beneficial to thermodynamic reactions. In addition, a comparison of the general alkali methods is carried out, and it is concluded that the KOH leaching process is thermodynamically superior to the conventional chromate production process.     

INFLUENCE OF HEAT TREATMENT ON DAMPING BEHAVIOUR OF THE MAGNESIUM WROUGHT ALLOY AZ61

The effect of isochronal heat treatments for 1h on variation of damping, hardness and microstructural change of the magnesium wrought alloy AZ61 was investigated. Damping and hardness behaviour could be attributed to the evolution of precipitation process. The influence of precipitation on damping behaviour was explained in the framework of the dislocation string model of Granato and Lücke.     

Theoretical Analysis for the Motion and Temperature of Melt Droplets in Spray Degassing Process

The motion of melt droplets in spray degassing process was analyzed theoretically. The height of the treatment tank in spray degassing process could be determined by the results of theoretical calculation of motion of melt droplets. To know whether the melt droplets would solidify during spraying process, the balance temperature of melt droplets was also theoretically analyzed. Then proof experiments for theoretical results about temperature of melt droplets were carried. In comparison, the experimental results were nearly similar to the calculation results.     

Growth Kinetics of Single Inclusion Particle in Molten Melts

On the basis of the single-particle framework, a new theory on inclusion growth in metallurgical melts is developed to study the kinetics of inclusion growth on account of reaction and collision. The studies show that the early growth of inclusion depends on reaction growth and Brawnian motion collision, and where the former is decisive, the late growth depends on turbulence collision and Stokes＇ collision, and where the former is dominant; collision growth is very quick during the smelting process, lessened in the refining process, but nearly negligible in the continuous casting process.     

Three-Dimensional Growth of Coherent Ferrite in Austenite: A Molecular Dynamics Study

Coherent second phase often exhibits anisotropic morphology with specifi c orientations with respect to both the second and the matrix phases. As a key feature of microstructure, the morphology of the coherent particles is essential for understanding the second-phase strengthening eff ect in various industrial alloys. This letter reports anisotropic growth of coherent ferrite from austenite matrix in pure iron based on molecular dynamics simulation. We found that the ferrite grain tends to grow into an elongated plate-like shape, independent of its initial confi guration. The fi nal shape of the ferrite is closely related to the misfi t between the two phases, with the longest direction and the broad facet of the plate being, respectively, consistent with the best matching direction and the best matching plane calculated via the Burgers vector content(BVC) method. The strain energy calculation in the framework of Eshelby's inclusion theory verifi es that the simulated orientation of the coherent ferrite is energetically favorable. It is anticipated that the BVC method will be applicable in analysis of anisotropic growth and morphology of coherent second phase in other phase transformation systems.     

An Easy Way to Quantify the Adhesion Energy of Nanostructured Cu/X(X=Cr,Ta,Mo,Nb,Zr) Multilayer Films Adherent to Polyimide Substrates

An approach based on film buckling under simple uniaxial tensile testing was utilized in this paper to quantitatively estimate the interfacial energy of the nanostructured multilayer films(NMFs) adherent to flexible substrates. The interfacial energies of polyimide-supported NMFs are determined to be *5.0 J/m2 for Cu/Cr, *4.1 J/m2 for Cu/Ta,*2.8 J/m2 for Cu/Mo, *1.1 J/m2 for Cu/Nb, and *1.2 J/m2 for Cu/Zr NMFs. Furthermore, a linear relationship between the adhesion energy and the interfacial shear strength is clearly demonstrated for the Cu-based NMFs, which is highly indicative of the applicability and reliability of the modified models.     

High-Speed Friction Stir Welding of SiC_p/Al–Mg–Si–Cu Composite

A 17 vol% SiCp/Al–Mg–Si–Cu composite plate with a thickness of 3 mm was successfully friction stir welded(FSWed) at a very high welding speed of 2000 mm/min for the first time. Microstructural observation indicated that the coarsening of the precipitates was greatly inhibited in the heat-affected zone of the FSW joint at high welding speed, due to the significantly reduced peak temperature and duration at high temperature. Therefore, prominent enhancement of the hardness was achieved at the lowest hardness zone of the FSW joint at this high welding speed, which was similar to that of the nugget zone. Furthermore, the ultimate tensile strength of the joint was as high as 369 MPa, which was much higher than that obtained at low welding speed of 100 mm/min(298 MPa). This study provides an effective method to weld aluminum matrix composite with superior quality and high welding efficiency.