玄武岩纤维纱线性能的试验研究

研究某种玄武岩纤维有捻纱的拉伸性能、耐高温性能以及耐酸碱性能。实验结果表明：在热稳定性试验中,该玄武岩纤维有捻纱的拉伸断裂强度在250℃之前随着温度的升高而增加,在250℃之后随着温度的升高而降低;在耐酸碱性试验中得出,该玄武岩纤维耐酸性强于耐碱性。     

玄武岩纤维贫混凝土力学性能研究

从贫混凝土基层的复合式路面的使用状况来看,反射裂缝的问题比较突出.玄武岩纤维贫混凝土是一种能有效减弱或者避免贫混凝土产生反射裂缝的新型混合料.通过一系列室内试验,对玄武岩纤维贫混凝土的抗压强度、抗弯拉强度、抗冲击能力以及静力抗压弹性模量等力学性能进行了系统研究.得出玄武岩纤维最佳掺量为混合料总质量的2.0‰,最佳掺量范围为3～6 kg/m3.掺入玄武岩纤维后,能大幅提高贫混凝土的早期抗压、抗弯拉强度,且28 d龄期的纤维贫混凝抗压强度和抗弯拉强度也较一般贫混凝土提高了20%以上;可使贫混凝土具有良好的抗冲击性能,较普通贫混凝土提高了近1/3倍;可提高贫混凝土材料的静力抗压弹性模量,但提升幅度不大.     

玄武岩短纤维增强环氧树脂复合材料的研究

以环氧树脂为基体、玄武岩短纤维为增强材料,制备了玄武岩短纤维/环氧树脂复合材料.研究了不同玄武岩短纤维含量对复合材料拉伸强度和耐磨性能的影响,采用扫描电子显微镜（SEM）观察了复合材料的断面形貌和磨损表面形貌,分析了磨损机制.结果表明,玄武岩短纤维/环氧树脂复合材料的抗拉强度和耐磨性能与纯环氧树脂相比均有不同程度的改善和提高,当玄武岩短纤维的含量为8%时,复合材料的拉伸强度最大;当玄武岩短纤维的含量为6%时,磨损率最低.随着玄武岩短纤维含量的增加,复合材料的磨损机制由黏着磨损向磨粒磨损转化.     

玄武岩纤维强度的统计分析

玄武岩纤维抗拉强度受限于各类缺陷,缺陷随机分布,其拉伸强度呈现出多分散性,分散性可用Weibull理论评价。本文采用Weibull理论及方法处理实验教据,计算出玄武岩纤维强度的二参数和三参数Weibull模数m,并阐述Weibull模数m与力学性能之间的关系。由统计数据结果得知,用三参数的Weibull分布可较好地表征玄武岩纤维的强度。通过扫描电镜观察了纤维表面形态,对其与玻璃纤维的强度差异做出解释。     

玻璃纤维和玄武岩纤维锚杆设计探讨

玻璃纤维和玄武岩纤维杆体材料具有耐腐蚀性、轻质、高强等优良特性,比钢筋或钢绞线更适于用作锚杆材料。测试玻璃纤维和玄武岩纤维杆体的物理力学性质,结合现行规范对两种材料作为锚杆的设计进行探讨。结果表明：玻璃纤维和玄武岩纤维杆体比普通钢筋等杆体材料的抗拉强度高,质量更轻,参考相关规范设计,适于作为锚杆应用于岩土工程锚固。     

不饱和聚酯挡风抑尘板力学性能研究

以玻璃纤维毡为增强骨架,不饱和聚酯树脂为基体材料,制备挡风抑尘板,并对不饱和聚酯树脂与玻璃纤维的配比、玻璃纤维的种类和固化剂、促进剂含量对挡风抑尘板力学性能的影响进行了研究。结果表明,当不饱和聚酯与玻璃纤维毡的质量比达到3∶1时,其拉伸强度和冲击强度都达到最大。高碱、中碱和无碱的玻璃纤维毡增强的挡风抑尘板拉伸强度分别达到55.198,75.249,89.446MPa,冲击强度分别达到30.699,35.367,41.343kJ/m2。而无碱玻璃纤维毡其拉伸强度比高碱提高了62%,比中碱提高了18.8%。冲击强度比高碱提高了34.7%,比中碱提高了16.9%。当促进剂质量分数为0.5%、固化剂质量分数为1%时,挡风抑尘板的拉伸强度最大为89.446MPa,冲击强度最大为41.343kJ/m2。     

玄武岩纤维增强聚合物混凝土基本力学性能试验研究

通过混凝土拌合物工作性能和基本力学性能试验,研究了不同掺量的玄武岩纤维和聚合物乳液在单掺、复掺情况下对混凝土工作性能、抗压强度和抗折强度的影响规律.结果表明:玄武岩纤维和聚合物乳液单掺时,随着玄武岩纤维或聚合物乳液掺量的增加,混凝土的7 d龄期抗压强度均略微降低,28 d龄期抗压强度提高不明显,抗折强度均有显著提高;在玄武岩纤维和聚合物乳液掺量匹配时,玄武岩纤维增强聚合物混凝土具有良好的工作性能和优异的抗折强度.     

Tensile and compression properties of Zr-based bulk amorphous alloy at different temperatures

Since the discovery of the Au-Si metallic amorphous alloy ribbon in 1960 by Duwez and co-workers[1] by rapid quenching, rapid developments have been obtained on the preparation of the amorphous alloy with the rapid quenching technique. However, from 1960 to 1989, the amorphous alloy could be only produced into forms of ribbon, flake, wire and powder due to the limitation of the cooling rate (>105 K/s). In the late 1980s, the Inoue group at Tohoku University in Sendai, Japan, investigated th…     

稻草纤维增强泡沫混凝土物理力学性能试验研究

为了研究稻草纤维增强泡沫混凝土的性能,以普通硅酸盐水泥为主要胶凝材料,硅灰、偏高岭土和粉煤灰为辅助胶凝材料,稻草纤维为增强材料,采用物理发泡法制备纤维增强泡沫混凝土;通过全因子试验,研究在不同水胶比和发泡剂掺量下,稻草纤维掺量对泡沫混凝土的密度、吸水率、抗压强度、抗折强度、劈裂抗拉强度和抗冻性能的影响。结果表明：对于不同水胶比和发泡剂掺量,泡沫混凝土的密度、抗压强度和劈裂抗拉强度均随纤维掺量的增加呈现出先增加后降低的变化规律;抗压强度随密度增加呈幂函数增加关系;劈裂抗拉强度随抗压强度的增加呈指数函数增加关系;当水胶比为0.45时,抗折强度随纤维掺量的增加先增加后降低,当水胶比为0.50时,抗折强度随纤维掺量的增加而增加;纤维的掺入增大了泡沫混凝土的泡孔尺寸和吸水率,降低了其抗冻性能。     

Thermo-plasticity of high-strength and high-ductility 7050 aluminum ingot

Thermo-plasticity of homogenized 7050 aluminum ingot was investigated by instantaneous tensile tests conducted at different temperatures. The results show that, with the increase of testing temperatures, the strength decreases, and the plasticity increases firstly and then decreases in homogenized 7050 ingot. When the studied alloy is deformed between 380 °C and 420 °C, the deformation resistance is lower and plasticity is better. And the actual heating temperature for ingot before hot extrusion should be controlled between 360 °C and 400 °C. At low tensile temperatures, the deformation structure is mainly composed of dislocation substructure. With the increase of testing temperatures, transgranular fracture transforms into intergranular fracture progressively during deformation. At high tensile temperatures, the grain boundaries are weakened, deformation is concentrated at the grain boundaries and the re-orientation of equilibrium phases at grain boundaries appears.     

APMP浆与针叶木化学浆组分配抄的纸张性能变化规律研究

将APMP浆全组分和APMP浆长纤维组分分别与针叶木浆全组分以及针叶木浆短纤维组分进行配抄,研究纸张抗张强度、撕裂强度和内结合强度的变化规律,探讨APMP浆与针叶木浆组分配抄对纸张性能的影响.结果表明:APMP浆与针叶木浆全组分配抄的抗张强度、撕裂强度、内结合强度随着针叶木浆添加量的增大而增大,与短纤维组分配抄时纸张抗张强度、撕裂强度在15%处发生转折;而针叶木浆分别与APMP浆全组分和长纤维组分配抄时,抗张强度、撕裂强度随着针叶木浆添加量的增大而增大.此外,APMP浆配抄的纸张,其纤维长度和本身强度对纸张强度性能的影响较大.随着针叶木化学浆的增加,纸页的可压缩性提高,短纤维组分对强度有一定的贡献.     

Relation of martensite-retained austenite and its effect on microstructure and mechanical properties of the quenched and partitioned steels

A two-step quenching and partitioning(QP) treatment was applied to low-carbon alloy steels. The relation of initial martensite- retained austenite- fresh martensite and its effect on microstructure and mechanical properties were investigated by experiments. The results reveal that the volume fraction of retained austenite can reach the peak value of 17%, and the corresponding volume fractions of initial martensite and fresh martensite are 40% and 43%, respectively, when the tested steel is treated by initial quenching at 330°C, partitioning at 500°C for 60 s and final quenching to room temperature. Moreover, the micromorphologies of austenite and martensite become finer with the increasing of initial martensite fraction. The elongation is the highest when the volume fractions of initial martensite and retained austenite are 70% and 11%, respectively, meanwhile, the yield strength increases and tensile strength decreases gradually with the increase of initial martensite fraction, which proves that the mechanical properties including elongation, yield strength and tensile strength are based on the comprehensive effect of the retained austenite fraction, the finer microstructure and austenite stability.     

Effects of quenching process on mechanical properties and microstructure of high strength steel

The effects of direct quenching and tempering (DQ-T) process and conventional reheat quenching and tempering (RQ-T) processes on mechanical properties and microstructure of high strength steel were investigated. The DQ process was found to enhance the hardenability of steel effectively. The tensile strength and yield strength of DQ specimen was 975 MPa and 925 MPa respectively, which were higher than those of RQ specimen??s of 920 MPa and 871 MPa. In contrast, low temperature toughness (?40 °C, AKV) of DQ-T specimen (124 J) was generally inferior to that of RQ-T specimen (156 J). The direct quenching temperature was one of the potential process parameters to determine strength/toughness balance of steel manufactured by DQ process. The experimental results showed that excellent strength/toughness balance was obtained when the specimens was quenched at temperature in the range of 850?C910 °C. The yield strength and impact energy (?40 °C) of DQ steel decreased significantly with increasing of quenching temperature, although the tensile strength was nearly stable.     

Effect of intermediate heat treatment temperature on microstructure and notch sensitivity of laser solid formed Inconel 718 superalloy

Inconel 718 superalloys deposited by laser solid forming (LSF) were heat treated with solution treatment,intermediate heat treatment (IHT) and two-stage aging treatment in sequence (SITA heat treatment).The effect of IHT temperature on microstructure,tensile property and notch sensitivity of LSFed Inconel 718 superalloy at 500 ℃ were investigated.As-deposited columnar grains have transformed to equiaxed grains and the grains were refined due to the recrystallization during the SITA heat treatment.It is found that the size and amount of δ phase dispersed at grain boundaries decreased with the increasing of IHT temperature,and δ phase disappeared when the IHT temperature reached 1 020 ℃.The ultimate tensile strength (UTS) and yield strength (YS) of smooth samples increased to a maximum when the IHT temperature reached 980 ℃ and then decreased slightly to a minimum when the IHT temperature was 1 000 ℃,and followed by slight increasing again till the IHT temperature reached 1 020 ℃,resulted from the competition of precipitation strengthening effect of γ″ and γ’ phase and the grain boundary weakening effect caused by the gradual disappearance of δ phase with increasing the IHT temperature.The notch sensitivity factor (qe) decreased but still greater than 1 as the IHT temperature increased,which is attributed to the decrease of the size and amount of δ precipitation.     

玻璃纤维增强环氧树脂单向复合材料力学性能分析

采用连续玻璃纤维与环氧树脂相复合,通过金属模压成型工艺,制备出单向玻璃纤维／环氧树脂复合材料。通过三点弯曲实验论证单向纤维对树脂基体的增强作用,从而研究不同纤维含量下复合材料的弹性模量、纵向拉伸强度、纵向压缩强度的变化趋势。结果表明：随着纤维含量的增加,复合材料的力学性能均增强,当纤维体积含量为50％时,其各项性能均较好,弹性模量为40GPa,纵向拉伸强度为1200MPa,纵向压缩模量为700MPa。此外,对复合材料的其他常用力学性能参数进行检测。     

Short-term mechanical properties of glass ionomer cement

The setting reaction of glass ionomer cement was studied by analyzing and comparing the short-tem mechanical properties of set cement stored in silicone oil, air and distilled water respectively at different temperatures. For the set cement stored at 37 °C, the strength of the sample in the air reached the maximum value after 24 h, then decreased to about 210 MPa and kept steady. The strength of the sample in water increased continuously and slowly, however, the increasing rate of sample stored in silicone oil was higher than that in the water. At 20 °C, the increasing rate of compressive strength for sample in air was higher than those in silicone oil and water. The diffusion speed and maintenance of water has significant effects on the mechanical properties of glass ionomer cements.     

不同增韧剂对尼龙/玻纤复合体系的增韧改性研究

将EPDM-g-MAH、POE-g-MAH、SEBS-g-MAH分别加入到尼龙66/玻璃纤维中,考察3种增韧体系对其机械性能的影响.通过对其机械性能和流变性能的研究,可知随EPDM-g-MAH、POE-g-MAH、SEBS-g-MAH份数的提高,尼龙66/玻璃纤维复合体系的冲击强度均有所提高,其中EPDM-g-MAH增韧效果最佳,POE-g-MAH次之,SEBS-g-MAH较次于前两者.EPDM-g-MAH加入量为9份时,体系的冲击强度是未增韧的2倍,拉伸强度降低.同时,熔体流动速率下降,平衡扭矩增大,说明增韧剂对体系起到增韧效果.     

Effect of High-temperature Annealing on Mechanical Performance and Microstructures of Different Oxygen SiC Fibers

In order to explore the effect of high-temperature annealing on the mechanical performances and microstructures of different oxygen SiC fibers, two types of silicon carbide(SiC)-based fibers, specified as XD-SiC fibers(low oxygen) and Nicalon-201 fibers(high oxygen), were annealed in Ar for 1 h at 800 ℃, 1 000 and 1 200 ℃, respectively. Mechanical properties of these fibers were characterized via a monofilament tensile method, with observation of the damaged monofilament by SEM. Also, the effects of annealing on the microstructure and chemical compositions of the fibers were studied. The experimental results indicated that the tensile strength decreased with the increase of annealing temperatures,after annealing-treatment at 1200℃, XD-SiC fibers remained 84% of its original strength, while Nicalon-201 fibers remained only 58% of its original strength. Crystallization and chemical composition of the fibers are the dominating factors for their mechanical performance at high temperatures. The microstructure changes of XD-SiC fibers are mainly composed of the growth of β-SiC, for Nicalon-201 fibers, evaporation of gases is the main change for microstructure.     

玄武岩纤维加固混凝土梁式结构的研究综述

玄武岩纤维复合材料(BFRP)是一种新型的加固材料,成为了代替碳纤维、玻璃纤维、芳纶纤维等传统加固材料的新一代复合加固材料.与碳纤维、玻璃纤维、芳纶纤维等相比,玄武岩纤维有耐高温、耐腐蚀、成本低廉、生产方便等优点.本文重点总结玄武岩纤维最近5年在国内的研究方向与成果,并分析玄武岩纤维在钢筋混凝土梁式结构中的应用与前景展望.     

水溶性维纶纤维的结构与性能研究

采用Nexus 870傅立叶红外光谱分析仪和DSC热分析仪分析水溶性维纶纤维的化学结构和热学性能.同时,采用单纤维强力仪测试水溶性维纶纤维的力学拉伸性能.得到水溶性维纶纤维及其在80℃的水中溶胀后试样玻璃化温度分别为43.6℃和-2.2℃;水溶性维纶纤维红外光谱图与标准聚乙烯醇红外光谱图在波数1 236cm^-1和621cm^-1处存在明显差别;单纤维拉伸速度一定时,试样夹持长度小,单纤维的断裂强度略大、断裂伸长率大、断裂功小.