IIb型与Ib型金刚石热稳定性比较

通过在铁基触媒中加入氮化硼的方法，高温高压合成了IIb型金刚石．用光学显微镜对IIb型金刚石与Ib型金刚石的单晶形貌结构进行观察．利用冲击韧性测定仪、静压强度仪及差热分析仪对IIb型金刚石与Ib型金刚石在空气中的热稳定性进行了系统的对比研究．结果一致表明，合成的IIb型金刚石较Ib型金刚石不仅具有优异的热冲击韧性和静压强度，而且具有较好的热稳定性，并通过差热分析提出了进一步提高金刚石热稳定性的有效地途径．金刚石的热分解过程与其重量的损失是同步的，表明失重是由金刚石石墨化和氧化引起的．     

优质金刚石的特征及其在工程钻头上的应用

通过热处理，静压强度实验，利用Ｘ射线衍射，发射光谱，ＸＴＬ－ＩＩ观察和分析了优质人造金刚石的特征，从晶形、强度、杂质、热稳定性４个主要方面进行了较系统的研究，并对其在工程钻头上的应用进行了探讨，结果表明：优质人造金刚石具有晶形好、强度高、杂质少、热稳定性优质等特点，高品级金刚石钻头能创造良好的经济效益，具有广阔的应用前景。     

气相氧化法在纳米金刚石提纯中的应用

为了推进纳米金刚石的工业化生产,对气相氧化法在炸药爆轰合成纳米金刚石的提纯应用进行了研究,并对使用气相氧化提纯方法与液相(王水浸泡、浓酸高温氧化)氧化法所得到的纳米金刚石的热稳定性和红外光谱分析进行了对比.结果表明:气相氧化提纯方法对纳米金刚石的特性影响不大,它在爆轰合成纳米金刚石提纯中的应用具有可行性.     

人造纳米金刚石研究现状与展望

针对静压法人工合成纳米金刚石面临着过高的压力和温度,其合成条件在国产六面顶金刚石压机上很难实现的问题,介绍了纳米金刚石的特殊性能和应用状况,概述了纳米金刚石的几种主要合成方法,在此基础上分析了合成过程中影响金刚石成核以及颗粒粒径的因素,提出了静压法制备纳米金刚石的可行性.     

纯铁触媒添加叠氮化钠合成高氮含量金刚石

氮元素是天然金刚石和人工合成金刚石中最主要的杂质。为了能够合成出与天然金刚石相同程度含氮量的金刚石,采用含添加剂叠氮化钠（NaN3）的纯铁粉末触媒和石墨在六面顶压机上进行合成研究。用傅立叶变换显微红外光谱仪对金刚石晶体中的氮含量进行细致的测试。结果表明,用含添加剂NaN3的纯铁粉末触媒合成的金刚石中以单一替代形式（Ib）存在的氮杂质最高浓度达到了2200 μg/g,这远远超过了迄今为止报道的用传统的金属触媒生长的具有完整晶形的金刚石中氮的最高含量800 μg/g,氮含量达到天然金刚石相同量级;当NaN3的含量小于0.7％时,金刚石中氮含量随着NaN3的含量增加而增加。     

聚晶金刚石热稳定性的研究

通过对3种聚晶金刚石在空气中差热和热重曲线的分析,了解了其在空气中的氧化方式．通过扫描电镜对高频感应加热的复合片进行了形貌观察,以了解其热损伤的程度．结合聚晶金刚石的差热曲线和SEM照片,确定以差热曲线的起始氧化温度作为其热稳定性的表征温度．结果表明：对应于复合片SYNDITE CTB002、CTB010、CTB025,热稳定性表征温度分别为650、690、720℃．     

PA6/PA11-b-PPG热塑性弹性体的合成及性能表征

以聚丙二醇为软段,以尼龙6(PA6)与尼龙11(PA11)为硬段,合成了一系列尼龙6/尼龙11-b-聚丙二醇(PA6/PA11-b-PPG)型热塑性聚酰胺性体(简称TPAE)。通过核磁分析与红外光谱测试表征了其化学结构,采用差示扫描量热法以及热重分析考察了TPAE的热性能。并测试了其动态热机械性能与力学性能。表征结果表明:1)合成的TPAE具有良好的热稳定性能;2)随着嵌段共聚物中尼龙11质量分数的增加,其玻璃化转变温度(T_g)逐渐降低;3)随着尼龙11质量分数的增加,TPAE的拉伸强度、弯曲强度逐渐降低,而冲击强度和断裂伸长率逐渐升高。     

聚酰亚胺型耐热感光高分子的热分解动力学

本文用热重分析法研究了聚酰亚胺型耐热感光高分子的热分解动力学.分别采用积分法、改进的积分法和微商法对实验数据进行了处理.后者只需一张热谱图,选用三次样条函数对热失重数据进行插值和微分,通过二元回归给出了热分解活化能、反应级数和频率因子,因此这是一种非常简便的方法.研究结果表明,笔者所合成的感光高分子具有优良的耐热性.     

四氢呋喃聚醚型聚氨酯预聚体增韧双酚A型氰酸酯树脂

以本体树脂双酚A型氰酸酯树脂(BCE)为扩链剂,改性四氢呋喃聚醚型聚氨酯预聚体(A)得到改性预聚体BA,用BA与BCE共聚共混以改善BCE树脂的韧性。确定了BCE/BA的固化工艺,考察了共聚共混体系静态力学性能、动态力学性能及热性能。结果表明,用BA与BCE树脂共聚共混,可有效提高氰酸酯树脂基体的韧性和强度。当BA用量为10份时,BCE/BA体系的冲击韧性比纯树脂提高了64%;当BA用量为20份时,增强增韧效果最佳,BCE/BA体系的冲击韧性可达14.5 kJ.m-2,比纯树脂提高了142%;弯曲强度为128 MPa,比纯树脂提高了23%。     

铁基触媒合成金刚石的压力功率动态匹配工艺研究

理论分析和生产实践都证明，在高温高压合成金刚石过程中合成腔体的压力和温度随着合成时间的延长而不断变化，即金刚石生长的工作点是漂移的.为避免合成腔体压力与温度的波动，为金刚石晶体的生长提供一个相对稳定的条件，应抑制工作点的漂移，主要的措施是采用非恒压力加压和非恒功率加热.使用粉末冶金铁基触媒进行了压力与功率动态匹配的金刚石合成工艺初探.实验发现，采用新工艺合成出的金刚石产量大，粒度粗，晶型好，机械性能高，主要性能指标均超过机械行业标准《人造金刚石技术条件》(JB/T7989 1997)对锯片级金刚石的技术要求，评级可在SMD30以上.     

Structures and Properties of High-Carbon High Speed Steel by RE-Mg-Ti Compound Modification

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 (ak), the fracture toughness (Klc)andt hreshold of fatigue crack growth (△Kth)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 reftned by the RE-Mg-Ti compound modification, the euteetic carbides are inclined to spheroidicize and are distributed everdy, 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 fractare toughness(Klc) and threshold of fatigue crack growth (△Kth) are improved in the meantime, the impact toughness (ak) is increased by over one time, and the rasistanee to thermal fatigue and wear resistanee at an elevated temperature are remarkably improved.     

新型耐高温水泥用于热采井固井初探

针对目前稠油热采井间封隔失效问题,探索了高铝水泥替代普通如砂水泥用于热采井固井的可行性、实验表明：体系中掺入所上加剂和适量微硅,能有效抑制其初期水化过快引起的闪凝,有助于提高浆体稳定性、降低渗透率并改善低温下水泥石早期强度,但微硅加量对高温下强度稳定性有一定影响。研究表明：高铝水泥具有良好的耐高温强度衰退及优良的综合工程性能,能满足稠油热采井固井的需要,具有良好的开发应用前景。     

Determination of relationships between thermal conductivityand material properties of rocks

Energy transfer between the adjacent parts of rocks in underground mines is widely influenced by the thermal conductivity of rocks. The relationships between the thermal conductivity and some material properties of rocks such as the uniaxial compressive strength, unit mass, tensile strength, cohesion, Young‘s modulus, point load strength, Schmidt rebound hardness, Shore scleroscope hardness and toughness strength were investigated. The statistical analysis of the data obtained in laboratory tests shows that the thermal conductivity increases with increasing the uniaxial compressive strength, unit mass, tensile strength, cohesion, Young‘s modulus, point load strength, Schmidt rebound hardness and Shore scleroscope hardness, and decreases with increasing the toughness strength.     

冻融循环作用下危岩体稳定性劣化机制及敏感参数分析

寒区危岩体常因温度起伏而受到冻融循环作用,使其力学性能劣化;而危岩体失稳破坏的实质是主控结构面的起裂和扩展问题,建立考虑断裂韧度劣化的危岩体稳定性分析方法能为寒区危岩体工程的长期稳定性评价提供理论依据.首先,根据断裂力学及冰冻结分离压力理论,考虑冻融循环作用对岩石Ⅰ型断裂韧度的劣化和结构面冻胀力,构建冻融循环作用下危岩...     

Twin-wire Submerged Arc Welding Process of a High-strength Low-alloy Steel

The measurement of thermal cycle curves of a high-strength low-alloy steel (HSLA) subjected twin-wire submerged arc welding (SAW) was introduced. The thermal simulation test was performed by using the obtained curves. The impact toughness at -50 ℃ temperature of the simulated samples was also tested. OM, SEM and TEM of the heat-affected zone (HAZ) of some simulation specimens were investigated. The results showed that the HSLA endured the twin-wire welding thermal cycle, generally, the low-temperature toughness values of each part of HAZ was lower than that of the parent materials, and the microstructure of coarse-grained zone(CGHAZ) mainly made up of granular bainite is the reason of the toughness serious deterioration. Coarse grain, grain boundary carbide extract and M-A island with large size and irregular polygon, along the grain boundary distribution, are the reasons for the toughness deterioration of CGHAZ. The research also showed that selected parameters of twin-wire SAW can meet the requirements to weld the test steel.     

聚乳酸/聚丙烯的共混改性及热学和力学性能

针对聚乳酸力学性能和耐热性差以及聚丙烯生物降解能力差等缺点,将聚乳酸和聚丙烯按照一定比例进行共混,以聚乙二醇为增容剂,采用双螺杆挤出机制备了聚乳酸/聚丙烯共混物,并分析了共混物力学性能和热学性能的变化.结果表明:共混物的结晶温度低于纯聚乳酸;当聚乙二醇的质量分数为9%时,共混物的两相达到完全相容,共混物的热稳定性和韧性得到提高,最大断裂伸长率为纯聚乳酸的3. 7倍,但拉伸强度和弯曲强度下降;共混物的热学和力学性能均优于聚乳酸和聚丙烯.     

空心玻璃微珠填充环氧树脂复合材料力学性能试验研究

在制备了不同配比改性空心玻璃微珠填充环氧树脂复合材料的基础上,对不同填充质量比的改性空心玻璃微珠（HGB）填充环氧树脂复合材料进行了准静态拉、压,简支冲击,应力松弛,动态力学行为等试验,得出了不同配比下材料的弹性模量、拉压强度、冲击韧度、应力松弛率、玻璃化转变温度等参数。试验发现,空心玻璃微珠的加入对材料的各项力学性能均产生了明显的改变。随玻璃微珠配比增加,材料的弹性模量、拉压强度大体上均呈现明显降低趋势;而冲击韧度、应力松弛率则有明显增强趋势;填充比为10%左右材料的耐热性最佳。以上研究发现对此类复合材料的研究和应用具有参考意义。     

添加Cu粉对Ni-Cr合金真空钎焊金刚石磨粒界面组织的影响

为降低金刚石高温钎焊后的热损伤,采用添加5%、10%、15%（wt%）Cu粉的Ni-Cr-B-Si钎料对金刚石磨粒进行了真空钎焊试验,实现了金刚石与钢基体的高强度连接.采用SEM对金刚石与钎料界面及碳化物形貌进行了观察分析。结果表明：添加5%Cu的Ni-Cr-B-Si钎料在1 050℃时钎焊能够实现金刚石与钎料的高强度连接,不仅对金刚石润湿较好,也能在一定程度上减少金刚石的热损伤。     

Structural characteristics and properties of PU-modified TDE-85/MeTHPA epoxy resin

Diglycidyl-4,5-epoxycyclohexane-1,2-dicarboxylate (TDE-85)/methyl tetrahydro-phthalic anhydride (MeTHPA) epoxy resin was modified by polyurethane(PU), and its structural characteristics and properties were studied by infrared spectrum analysis (IR), scanning electronic microscopy (SEM), mechanics testing and thermogravimetric analysis (TG). The results indicate that epoxy polymeric network I and polyurethane polymeric network II are formed in the PU-modified TDE-85/MeTHPA epoxy resin. Meanwhile the PU-modified TDE-85/MeTHPA resins have heterogeneous structure. The miscibility between epoxy (EP) and polyurethane (PU) as well as the phase size are dominantly determined by the mass fraction of polyurethane prepolymer (PUP) in the EP/PU blends. With the increase of PUP mass fraction, the tensile strength, impact strength and thermal stability of the PU-modified TDE-85/MeTHPA epoxy resin all firstly exhibit increasing tendency, and decrease after successively reaching their maxima. When the number-average molecular mass of PPG is 1 000 and the mass fraction of PUP is 15%, the tensile strength, impact strength and thermal stability of materials obtained, compared with TDE-85/MeTHPA epoxy resin, are improved obviously.     

Elevated-temperature properties of one long-life high-strength gun steel

The hardness, tensile strength and impact toughness of one quenched and tempered steel with nominal composition of Fe0.25C-3.0Cr-3.0Mo-0.6Ni-0. 1Nb (mass fraction) both at room temperature and at elevated temperatures were investigated in order to develop high-strength steel for long-life gun barrel use. It is found that the steel has lower decrease rate of tensile strength at elevated temperature in comparison with the commonly used G4335V high-strength gun steel, which contains higher Ni and lower Cr and Mo contents. The high elevated-temperature strength of the steel is attributed to the strong secondary hardening effect and high tempering softening resistance caused by the tempering precipitation of fine Mo-rich M2C carbides in the α-Fe matrix. The experimental steel is not susceptible to secondary hardening embrittlement, meanwhile, its room-temperature impact energy is much higher than the normal requirement of impact toughness for high strength gun steels. Therefore, the steel is suitable for production of long-life high-strength gun barrels with the combination of superior elevated-temperature strength and good impact toughness.