Effect of intergranular β phase on the rupture plasticity of the low expansion Inconel 783 superalloy

High temperature rupture specimens with different rapture plasticity are investigated. The rupture fracture failure of Inconel 783 superalloy is researched by analyzing the fracture surface and microstructure of the rupture specimens. The intergranular β phase precipitated sufficiently with favorable morphology can efficiently strengthen grain boundaries that can achieve a full plastic deformation of grains. Additionally, the intergranular β phase can effectively restrain the occurrence and expansion of intergranular cracks during the rupture test. The intergranular β phase insufficiently precipitated can weaken the intergranular cohesion and lead to the occurrence and expansion of cracks; thus, the grains cannot be fully deformed before breaking. Therefore, the β phase precipitated in the grain boundaries can significantly increase the rupture plasticity of Inconel 783 superalloy.

X-ray diffraction study of effect of deposition conditions on α-β phase transition and stress evolution in sputter-deposited W coatings

Pure W and W-Cu-W trilayer coatings were deposited on an Fe substrate by d.c. magnetron sputtering. The α-β phase evolution, intragranular stress evolution in sputter-deposited W layer were investigated by x-ray diffraction. They are directly related to the film microstructure, density and adhesion. Therefore, control of the film stress and phase component transition is essential for its applications. The phase component transition from β-W to α-W and intragranular stress evolution from tensile to compressive strongly depend on the deposition parameters and can be induced by lowering Ar pressure and rising target power. The compressively stressed films with α-W phase have a dense microstructure and high adhesion to Fe substrate.

Characterization of the β Phase Decomposition in Ti-5Al-5Mo-5V-3Cr at Slow Heating Rates

The influence of slow heating rates: 2, 5, 10 and 30?C/min (0.033, 0.083, 0.166 and 0.50℃/s) on the β phase decomposition of Ti-5Al-5Mo-5V-3Cr (Ti-5553) during continuous heating were characterized by differential scanning calorimetry (DSC) analysis, light microscopy, scanning electron microscopy, X-ray diffraction and hardness testing. Starting microstructure was the β phase obtained by heating the Ti-5553 above the Tβ temperature and a water quench. Results show that heating rate has a significant impact on the precipitation mechanisms and on the β→α transformation in this range of heating rates. The main formation of α precipitates occurs between 500 and 600℃at all heating rates tested.A heating at 2℃/min produces very fine and homogeneously distributed α plate precipitates which have nucleated on the nanometer size ωiso precipitates. The ωiso precipitates between 350 and 400℃. At higher heating rates 10, 15 or 30℃/min, the amount of precipitation of ωiso is lower so an additional formation of nanometer size precipitates occurs between 450 and 500℃ It is supposed that both precipitates act as nucleation sites for α phase precipitation. The resultant microstructure consists in a fine intragranular distribution of α precipitates and a coarser precipitation of α at the grain boundaries. It is shown that the precipitation of ωiso phase retards or prevents the precipitation of nanometer size precipitates occurring between 450 and 500℃. This cannot be generalized to all the β-metastable titanium alloys since Ti-LCB does not exhibit the same heating rate dependence on DSC curves.

基于β-糊精氧化石墨烯管尖固相萃取/高效液相色谱检测生活饮用水中苯并[a]芘

以自制的β-糊精氧化石墨烯(β-CD@GO)装填入10mL移液器吸头作为固相萃取剂,结合高效液相色谱法对生活饮用水中苯并[a]芘进行检测,并对固相萃取条件进行了优化。苯并[a]芘在0.1~50μg/L范围内线性关系良好(r=0.9996),检出限为3ng/L(S/N=3)。在加标水平为0.5、5、40μg/L时,方法回收率为89.2%~92.5%,相对标准偏差为3.7%~5.2%。该方法操作简便快速、选择性好、灵敏度高、有机溶剂消耗少,可用于生活饮用水中苯并[a]芘快速检测分析。

Evolution of microstructure and phase composition of Ti-3Al-5Mo-4.5V alloy with varied β phase stability

The microstructure evolution and phase composition of an α+β titanium alloy, Ti-3Al-5Mo-4.5V(wt.%),have been investigated. Electron probe micro analysis(EPMA) quantitative results manifest that the stability of β phase decreases with increasing quenching temperature, which is influenced by the significant variation of β-stabilizing elements concentration. Detailed microstructure analysis shows that the β→ωphase transformation does occur when quenching at 750℃ and 800 ℃. The ω-reflections change from incommensurate ω-spots(750 ℃) to ideal ω-spots(800 ℃) as the β stability of the alloy decreases. Further the decrease of β phase stability encourages the formation of athermal α " martensite, which has the following orientation relationships: [111]β//[110]α",[100]p//[100]α " and [-110]p//[00-1]α" with respect to the β matrix.

Mechanical properties and deformation mechanisms of Ti-3Al-5Mo-4.5V alloy with varied β phase stability

Evolution of deformation mechanisms and mechanical properties of Ti-3Al-5Mo-4.5V alloy with different β phase stability have been systematically investigated. β phase stability alteration is achieved through quenching temperature variation from dual α+β field(700℃) to single β field(880℃). Tensile tests at ambient temperature show that apparent yield strength of the alloy experiences an abrupt decrease followed by a significant increase from 700℃ to 880℃. Work hardening behavior is characterized by transition from the initial two-regime feature to the three-stage outlook. Concurrently, the maximum working hardening rate drops from 14000 MPa to 3000 MPa, which is concurrent with the shrinking volume fraction of primary a phase. Detailed discussion about the relationship between deformation mechanisms and β phase stability has been outlined.

稳定化处理和Cu元素含量对罐盖用5182铝合金板材β相分布的影响

研究了两种Cu元素含量的罐盖用5182铝合金成品板材经不同温度稳定化处理后的β相分布情况。结果表明:(1)当稳定化温度低于120℃时,两种板材均有大量β相沿晶界和剪切带连续析出;当稳定化温度为160℃时,两种板材β相连续析出现象显著减少;当稳定化温度高于160℃时,随稳定化温度的升高,β相连续析出现象逐渐减少;当稳定化温度为220℃时,β相分布最均匀,无明显连续析出现象,推测此时材料的抗应力腐蚀断裂敏感性最佳。(2)Cu元素质量分数为0.1%的5182板材比Cu元素质量分数为0.06%的5182板材β相析出更少,分布更均匀。

Influences of Alloying Elements W, Mo, Cr and Nb on Retained Beta Phase in 47Al Based near γ-TiAl Alloys

The influences of alloying elements W, Mo, Cr, and Nb on retained ft phase in 47AI based near 7-TiAI alloys have been studied. The results reveal that the amount of retained β phase is increased by the addition of Cr, Mo, W in rising rank, although the distribution of β phase in Cr-bearing alloys is different from that of Mo- or W-bearing alloys. For Nb-doped alloys, no retained ft was found even when 5 at. pct Nb was added. The as-cast microstructural features and the distribution of the b phase in the different alloy families were compared and interpreted in terms of the different segregation behaviour of these elements in Ti.

超高效液相色谱-串联质谱法检测卤肉中4种β-受体激动剂残留

建立了一种超高效液相色谱串联质谱(ultra-high performance liquid chromatography-tandem mass spectrometry,UPLC-MS)检测卤肉中4种β-受体激动剂(特布他林、克仑特罗、莱克多巴胺、沙丁胺醇)的方法。样品经β-盐酸葡萄糖醛酸苷酶/芳基硫酸酯酶解后,经SLS固相萃取柱净化。以0.1%甲酸水和乙腈为流动相梯度洗脱,用Thermo Hypersil Gold C_(18)色谱柱分离,ESI+进行多反应监测(MRM),内标法定量。4种β-受体激动剂在浓度为0.5~9.5μg/L范围内线性关系良好,相关系数(r)均大于0.9988,检出限(LOD)为0.1μg/kg,定量限(LOQ)为0.3μg/kg。3个加标水平下(1、5、9μg/kg)的回收率在87.9%~113.7%之间,RSD为1.48%~9.32%。162批次卤肉样品,有一份卤猪蹄样品检出克伦特罗含量为1.51μg/kg,莱克多巴胺为3.65μg/kg;另外一份卤羊肉样品检出克伦特罗含量11.5μg/kg。本方法快速准确,可用于卤肉中4种β-受体激动剂(特布他林、克仑特罗、莱克多巴胺、沙丁胺醇)的定性、定量检测。

共混β-环糊精改性PVDF膜的制备及性能

以N,N-二甲基乙酰胺(DMAc)为溶剂、聚乙二醇20000(PEG 20000)和聚乙烯吡咯烷酮K30(PVP K30)为致孔剂,以β-环糊精(β-CD)为添加剂进行共混改性,采用非溶剂致相分离法(NIPS)制备了β-CD共混改性聚偏氟乙烯(PVDF)膜。考察了β-CD添加量对改性膜微观形貌、渗透性能和截留性能、亲水性和抗污染性能的影响。结果表明,添加β-CD后改性膜表面开孔数量及孔径增加,膜截面皮层变薄,亚层发展出小指状孔,贯通的大指状孔数量降低,指状孔壁上出现更为疏松的大孔结构。添加β-CD后改性PVDF膜的纯水通量和牛血清蛋白(BSA)截留率均大幅提高,其中β-CD添加量为4%时改性膜的综合性能最佳,其纯水通量为1848 L/(m^(2)·h·bar),BSA截留率为90.43%。添加β-CD后改性膜动态水接触角下降为0°的时间减少,说明其内在湿润性增强。改性膜在渗透性能和分离性能提高的同时保持了较好的抗污染性能,所有膜的通量恢复率均达到98%以上。

异丁香酚-β-D-葡萄糖苷的合成及热裂解转移率

以乙酰溴-α-D-葡萄糖(Ⅰ)作为糖基供体与异丁香酚(Ⅱ)进行反应,通过相转移催化法和离子液体催化法合成了异丁香酚-2,3,4,6-四-O-乙酰基-β-D-葡萄糖苷(Ⅲ),然后在甲醇钠中脱乙酰化得到异丁香酚-β-D-葡萄糖苷(Ⅳ)。将化合物Ⅳ加入卷烟中,测试了其在卷烟主流烟气粒相中的转移率。结果表明,合成Ⅲ采用离子液体催化法(收率56.8%)优于相转移催化法(收率43.5%)。离子液体催化法反应条件为:1-丁基-3-甲基-溴化咪唑为催化剂、氯仿为溶剂、氢氧化钠水溶液为缚酸剂、n(Ⅰ)∶n(Ⅱ)=0.8∶1,n(Ⅰ)∶n(1-丁基-3-甲基-溴化咪唑)=1∶1、室温、反应时间8 h。在上述条件下,化合物Ⅲ的收率为56.8%。化合物Ⅲ在甲醇钠/甲醇溶液中反应脱去四乙酰基,得到化合物Ⅳ,收率87.6%。卷烟燃吸过程中,化合物Ⅳ热裂解为异丁香酚,异丁香酚向主流烟气粒相中的转移率为3.2%。

血清孕酮、β-HCG、INF-γ及IL-10检测预测黄体功能不足性流产患者保胎结局的价值

目的探讨血清孕酮、β-绒毛膜促性腺激素(β-HCG)、γ干扰素(INF-γ)及白介素-10(IL-10)检测预测黄体功能不足性流产患者保胎结局的价值。方法回顾性选取2021年1月至2022年12月在西北妇女儿童医院治疗的96例黄体功能不足先兆性流产患者纳入观察组,选择同期产检的103例健康孕妇纳入对照组,比较两组孕妇孕6周、8周及10周的血清孕酮、β-HCG、INF-γ及IL-10水平;按观察组孕妇的保胎结局分为保胎成功组74例和妊娠失败组22例,采用Pearson法分析血清孕酮、β-HCG、INF-γ及IL-10水平与保胎结局的相关性,绘制受试者工作特征曲线(ROC)得到曲线下面积(AUC),以AUC评价孕酮、β-HCG、INF-γ及IL-10对黄体功能不足性先兆流产患者保胎结局的预测效能。结果观察组孕妇孕6周、8周和10周的孕酮、β-HCG和IL-10水平明显低于对照组,但INF-γ水平明显高于对照组,差异均有统计学意义(P<0.05);保胎成功组孕妇孕10周孕酮、β-HCG]及IL-10水平明显高于妊娠失败组,但INF-γ明显低于妊娠失败组,差异均有统计学意义(P<0.05);经Pearson相关性分析结果显示,孕10周孕酮、β-HCG及IL-10与保胎结局呈正相关(P<0.05),INF-γ与保胎结局呈负相关(P<0.05);经ROC分析结果显示,孕10周的孕酮、β-HCG、INF-γ及IL-10预测黄体功能不足先兆性流产患者保胎结局的AUC分别为0.953、0.853、0.897、0.875,均具有较好预测价值(P<0.05)。结论孕酮、β-HCG、IL-10及INF-γ与黄体功能不足先兆性流产患者保胎结局密切相关,可作为其保胎结局的预测指标。

Effect of Substrate Characteristics on Interdiffusion Coefficients of Ni and Al Atoms in β-NiAl Phase of Aluminide Coatings

Interdiffusion coefficients at 950℃ and 1050℃ are calculated by Wagner analysis method as a function of composition of β-NiAI phase. The β-NiAI phase is formed by pack cementation on surface of superalloy. Results of the calculation show that interdiffusion coefficients in β-NiAI phase strongly depend on the compositions and vary over several orders of magnitude. Compared with the interdiffusion coefficients in the stoichiometric β-NiAI phase, the interdiffusion coefficients in β-NiAI phase formed on superalloy is obviously small, probably due to the composition, complicated microstructure and precipitates. However, it could be seen clearly that the shapes of the diffusivity curves are very similar to each other. The similarity of the diffusion curves and the difference between interdiffusion coefficients imply that the compositions, microstructures and precipitates of superalloy have a distinctly adverse effect on the interdiffusion of Ni and Al atoms during aluminization, but do not change the essential characteristics of β-NiAI phase.

Increasing the Content of β Phase of Poly(9,9-dioctylfluorene) by Synergistically Controlling Solution Aggregation and Extending Film-forming Time

For poly(9,9-dioctylfluorene)(PFO),β phase (coplanar conformation with the intra-chain torsion angle of 165°) has a greater conjugation length and higher degree of order compared to those of α phase, which favors charge carrier transport. However, the highest content of β phase obtained so far is 45%. We propose to increase the content of β phase by promoting the solution aggregation of PFO molecules and extending film-forming time. For this purpose, 1,8-diiodooctane (DIO) is added to PFO o-xylene solution, which enhances the interaction of PFO chains and improves the planarity of PFO backbone, resulting in the formation of ordered aggregation. The aggregates act as nucleation centers to promote the formation of β phase. The content of β phase increases with increasing DIO concentration and reaches a platform of 39% as DIO is more than 4 vol%. Furthermore, the film is kept in a sealed environment with oxylene atmosphere for 3 h, thus the PFO molecules have enough time to diffuse to the crystallization front and achieve disorder-order transition. As a result, the crystallinity of PFO is improved significantly and the content of β phase increases to 52%, reaching the highest value reported so far.

Partitioning and purification of extracellular β-1,3-1,4-glucanase in aqueous two-phase systems

The partition behaviors of β-1,3-1,4-glucanase, α-amylase and neutral proteases from clarified and whole fermenta-tion broths of Bacillus subtilis ZJF-1A5 were investigated. An aqueous two-phase system (polyethylene glycol (PEG)/MgSO4) was examined with regard to the effects of PEG molecular weight (MW) and concentration, MgSO4 concentration, pH and NaCl concentration on enzyme partition and extraction. The MW and concentration of PEG were found to have significant effects on enzyme partition and extraction with low MW PEG showing the greatest benefit in the partition and extraction of β-glucanase with the PEG/MgSO4 system. MgSO4 concentration influenced the partition and extraction of β-glucanase significantly. pH had little effect on β-glucanase or proteases partition but affected α-amylase partition when pH was over 7.0. The addition of NaCl had little effect on the partition behavior of β-glucanase but had very significant effects on the partitioning of α-amylase and on the neutral proteases. The partition behaviors of β-glucanase, α-amylase and proteases in whole broth were also investigated and results were similar to those obtained with clarified fermentation broth. A two-step process for purifying β-glucanase was developed, which achieved β-glucanase recovery of 65.3% and specific activity of 14027 U/mg, 6.6 times improvement over the whole broth.

Effects of Stretching Ratio and Temperature on Phase Transition of Melt-spun Poly(Vinylidene Fluoride) Fibers

The effects of stretching ratio and stretching temperature on pbase transition of melt-spun poly （ vinylidene fluoride ） fibers were investigated and analyzed by using scanning electron microscopy, wide angle X- ray diffraction, differential scanning calorimetry and Fourier transfer infrared spectroscopy. The β phase exists in the as-spun fiber. The β phase content increases as the stretching ratio increases. When the stretching temperature is lower than 100 ℃ , enhancing temperature is good for the transition of phase a to ft. By contrast, when the stretching temperature is higher than 100 ℃ , enhancing temperature is unfavourable for the transition of phase a to β. Increasing the draw temperature increases the α-phase content.

Improvement of β-phase crystal formation in a BaTiO3-modified PVDF membrane

In this paper,low temperature plasma is used to modify the surface of barium titanate（BaTiO3）nanoparticles in order to enhance the interfacial compatibility between ferroelectric poly（vinylidene fluoride）（PVDF） and BaTiO3 nanoparticles.The results demonstrate that oxygenic groups are successfully attached to the BaTiO3 surface,and the quantity of the functional groups increases with the treatment voltage.Furthermore,the effect of modified BaTiO3 nanoparticles on the morphology and crystal structure of the PVDF/BaTiO3 membrane is investigated.The results reveal that the dispersion of BaTiO3 nanoparticles in the PVDF matrix was greatly improved due to the modification of the BaTiO3 nanoparticles by air plasma.It is worth noting that the formation of a β-phase in a PVDF/modified BaTiO3 membrane is observably promoted,which results from the strong interaction between PVDF chains and oxygenic groups fixed on the BaTiO3 surface and the better dispersion of BaTiO3 nanoparticles in the PVDF matrix.Besides,the PVDF/modified BaTiO3 membrane at the treatment voltage of 24 k V exhibits a lower water contact angle（≈68.4°） compared with the unmodified one（≈86.7°）.Meanwhile,the dielectric constant of PVDF/BaTiO3 nanocomposites increases with the increase of working voltage.

Preparation of nanometer δ- and β-bismuth trioxide by vacuum vapor-phase oxidation

A stable δ- and β-bismuth trioxide was prepared at room temperature by vacuum vapor-phase oxidation. The average crystal size of products was 14.6 nm (by XRD), the d(0.5) value was in the range from 62 nm to 69 nm, and geometric standard deviation(GSD) was from 1.42 to 1.64. The results show that δ-Bi2O3 is formed when quenching rates is rapid and β-Bi2O3 is formed when it is slow. The size of grains increases with rising reaction temperature, flow rate of carrier gas, residual pressure of system and longer growing time of grains.

Nuclephilic ring opening of epoxides promoted by multi-site phase-transfer catalyst:An efficient and eco-friendly route to synthesis of β-hydroxythiocyanate

A highly effective and mild protocol for ring opening of epoxides with NH4SCN in the presence of catalytic amount of a multi- site phase-transfer catalyst, α,α＇,α＂-N-hexakis（triethylammoniummethylene chloride）-melamine, is developed. A variety of ^-hydroxy thiocyanates as important intermediates in agricultural and pharmaceutical chemistry were obtained in high yields with excellent regioselectivity and in short reaction times. 2009 Ali Reza Kiasat. Published by Elsevier B.V. on behalf of Chinese Chemical Society. All rights reserved.

MULTIPLE MELTING BEHAVIOR OF β-CRYSTALLINE PHASE POLYPROPYLENE

Differential scanning calorimetry and X-ray diffraction experiments on β-nucleated polypropylene were made on the samples crystallized at different temperatures and processed by injection molding. The crystal perfection was shown to vary with crystallization temperature. The observed multiple peaks could be related to a ill-phase with defective inclination of the chains, a recrystallized or original β_2-phase of more perfect inclination, and the α-phase. Injection molded samples could be analyzed from the established DSC interpretation.