长期时效下15Cr1Mo1V钢的显微组织及力学性能

通过常温力学性能试验、高温力学性能试验、显微组织分析、扫描电镜(SEM)及能谱(EDS)分析研究了长期时效对15Cr1Mo1V钢的显微组织和力学性能的影响。结果表明:15Cr1Mo1V钢在时效过程中硬度和强度逐渐下降,塑性和韧性变化不明显;组织发生老化,贝氏体区域逐渐分解消失,颗粒状碳化物析出长大并向晶界转移聚集,最终在晶界处呈链状分布; V、Mo元素随碳化物析出并向晶界处聚集,使基体中的合金元素贫化,弱化了合金元素的固溶强化和沉淀强化作用,是导致材料硬度和强度性能发生劣化的主要原因。     

不同截面尺寸Cr8Mo2SiV和Cr12Mo1V1钢的组织与性能

对不同截面尺寸Cr8Mo2SiV和Cr12Mo1V1冷作模具钢的组织,共晶碳化物尺寸及不均匀度,冲击性能进行了研究。结果表明,Cr8Mo2SiV钢和Cr12Mo1V1钢退火组织均为球状珠光体上分布着碳化物;随热轧截面尺寸的增大,碳化物尺寸变大,分布均匀性变差。适当减小试验钢的截面尺寸,能够显著减小共晶碳化物的尺寸并改善其分布不均度,提高材料的冲击性能。     

Cr12Mo1V1冷轧工作辊淬火工艺研究

采用冲击、硬度、金相、X射线衍射等手段,研究Cr12Mo1V1钢在不同温度淬火、油冷后试样的组织性能.结果表明:在一定的温度范围内,Cr12Mo1V1钢的冲击韧度先下降后上升,硬度先升高后降低 最终确定Cr12Mo1V1钢的佳淬火温度为1020℃.     

Co对4Cr5Mo2V钢组织和强韧性的影响

采用OM、SEM、EDS、硬度测试、室温冲击及高温拉伸等方法研究了Co对4Cr5Mo2V钢的组织和强韧性的影响。结果表明:经1010 ℃淬火30 min,4Cr5Mo2V-Co钢未溶碳化物数量更多,马氏体板条更细;510~600 ℃回火时,4Cr5Mo2V-Co钢的回火硬度较4Cr5Mo2V钢高出1~2 HRC,但二者冲击性能相当;相同初始硬度条件下,4Cr5Mo2V-Co钢具有更高的高温强度,这是因为Co元素的添加促进了4Cr5Mo2V-Co钢二次硬化碳化物的形核速率,并能降低碳化物的粗化速率,从而提高了4Cr5Mo2V-Co钢的强度。     

10Cr9Mo1VNb钢TLP接头高温力学性能

10Cr9Mo1VNb钢管多用于高温环境,采用TLP焊接10Cr9Mo1VNb钢,分别在650℃、680℃保温500h,分析了不同保温温度下10Cr9Mo1VNb钢管TLP焊接头的显微组织和力学性能.试验结果表明:当保温温度为650℃时,TLP焊接接头的力学性能略下降,晶粒增大,晶间出现了少量碳化物聚集.得出M23C6碳化物是10Cr9Mo1VNb钢管TLP焊接头保持高温力学性能稳定性的重要因素;但当保温温度达到680℃,碳化物的积聚程度增加,Cr、Mo在a-Fe中的扩散能力有所增加,微量Cr、Mo迁移到碳化物中,导致固溶强化减弱,接头高温力学性能稳定性下降.     

热处理工艺对9Cr1Mo力学性能及耐腐蚀性能的影响

探究不同淬火和回火温度对9Cr1Mo合金钢力学性能和耐腐蚀性能的影响，通过对微观形貌观察发现，较高的淬火温度能够保证钢中碳化物的充分溶解，提高组织均匀性，同时减少晶界密度，提高耐腐蚀能力；较低的回火温度可控制合金元素在钢中的迁移速度，从而减少晶界处富Cr碳化物析出。较高的淬火温度和较低的回火温度能够保证微观组织均匀，不会形成元素富集区，在保证了较佳的力学性能的同时还能提高金属的耐腐蚀性能。     

高温螺栓恢复热处理的研究

通过对在长期高温下运行的已失效螺栓分析,发现沿晶界有碳化物析出,形成网状晶界,使晶界原子结合力下降,晶界弱化,在工作应力长期作用下,网状晶界会产生裂纹并扩展,使螺栓冲击韧度下降,具有热脆化倾向.通过研究螺栓恢复热处理工艺,结果表明,25Cr2Mo1V钢螺栓的恢复热处理工艺为:980℃二次正火+680℃×6h回火;25Cr2MoV钢螺栓的恢复热处理工艺为:960℃正火+900℃正火+650℃×6h回火.     

奥氏体化过程对Cr14Mo4V高温轴承钢微观组织的影响

针对高温轴承钢Cr14Mo4V开展了微观组织随奥氏体化参数演化规律研究。利用OM、XRD、SEM及硬度测试对Cr14Mo4V钢中碳化物、残留奥氏体、晶粒尺寸及硬度等进行了分析。结果表明,淬火态Cr14Mo4V高温轴承钢微观组织主要包括淬火马氏体、残留奥氏体和带状碳化物;奥氏体化过程中微观组织演化对奥氏体化温度较为敏感,随着奥氏体化温度的升高,残留奥氏体含量逐渐增加,晶粒尺寸逐渐增大,碳化物逐渐溶解,带状碳化物合金元素分布发生变化。Cr14Mo4V轴承钢硬度随奥氏体化温度的升高呈先略微增加后显著降低的趋势,主要受基体固溶度、残留奥氏体含量及晶粒尺寸等因素综合影响。     

运行1.2×105 h 15Cr1Mo1V钢主蒸汽管及R317焊缝的组织和性能

以某电厂运行12万小时的15Cr1Mo1V钢主蒸汽管及R317焊缝作为研究对象,对其显微组织及室温、高温力学性能进行了研究,并对其在560℃下的安全服役状态进行了分析。结果表明:服役态管组织中无贝氏体区域,晶界上碳化物聚集长大,晶内存在细小弥散碳化物,组织有一定的老化现象;与供货态相比,服役态管力学性能均有一定的下降,室温抗拉强度下降幅度较小,高温下的力学性能下降幅度较大;服役态管R317焊缝具有明显的脆化现象,应防止其在冷态下受到较大的冲击而产生裂纹; 15Cr1Mo1V钢和R317焊缝可以满足560℃下的安全服役。     

15Cr1Mo1V高压锅炉管的开发及其高温组织稳定性研究

15Cr1Mo1V是俄罗斯标准的高压锅炉管用钢牌号,该钢种具有较高的热强性和高温抗氧化性,在俄罗斯以及我国的电厂均有应用。介绍15Cr1Mo1V钢管的生产工艺,检验成品钢管的室温力学性能、四象限硬度性能及金相组织,分析其组织稳定性。试验结果表明:15Cr1Mo1V钢管的成分设计和热处理工艺合理,产品性能优良,全部检验性能符合ТУ14-3P-55—2001标准要求;成品15Cr1Mo1V钢管组织为F+B,组织均匀,无黄块状组织;该产品在高温下的组织稳定性好。     

Electrical conductivity of 1 : 1 and 2 : 1 clay minerals

The A.C. impedance plots were used as tools to analyze the electrical response of two varieties of Tunisian halloysite 1: 1 and illitic samples 2: 1 as a function of frequency at different temperatures (80–800°C). The real and imaginary parts of the complex impedance trace semicircles in the complex plane. Except for the illite, It-1, the second sample analyzed in this study, these plots give evidence for the presence of both bulk and grain boundary effect, above 600°C onwards. The bulk resistance of the materials decreases with the rise in temperature. Impedance Spectroscopy data reveal a non-Debye type of dielectric relaxation. The Nyquist plots show the negative temperature coefficient of resistance of both pure Tunisian illite and halloysite samples. The results of bulk electrical conductivity and its activation energy are presented for the two mineral clay samples. For illite It-1, the activation energy values estimated from the AC conductivity pattern and modulus pattern are very similar and suggest a possibility of a long-range mobility of charge carriers (ions) via hopping mechanism of electrical transport processes at higher temperature. On the other hand, for the halloysite sample provided from kasserine, (Ha-Kass), the modulus analysis admit that the electrical transport processes of the material are very likely of electronic nature. Relaxation frequencies follow an Arrhenius behavior with the activation energy values not comparable to those found for the electrical conductivity.     

A contribution to the crystallochemistry of ternary 1:1:1 and 1:1:2 rare earth intermetallic phases with Pb and Pd

The ternary alloys of the rare earths with lead and palladium were studied for the stoichiometric ratios 1:1:1 and 1:1:2 with respect to the structure of these alloys and their existence field. RPbPd (R = La, Ce, Pr, Nd, Sm, Gd, Tb, Dy, Y, Ho, Er, Tm, Yb) compounds have a hexagonal structure, hP9 Fe₂P type, while RPbPd₂ (R = Pr, Sm, Gd, Tb, Dy, Ho, Er, Yb) alloys have the cubic AlCu₂Mn-type structure (cF16, BiF₃ superstructure).     

有机阴离子转运多肽1B1的遗传药理学进展

人体存在多种类型的药物转运体,对于药物的吸收、分布和排泄起重要作用。参与药物跨膜转运的转运体功能受影响,将可能导致诸多临床药物的疗效、毒副作用甚至药物相互作用的发生。在各种影响因素中,遗传多态性所起的作用最为重要,可导致基因表达和蛋白功能发生改变。目前,阐明转运体基因的多态性以及基因型与表型之间的相互关系已成为应用遗传信息指导临床个体化用药的必要步骤。本文就肝脏有机阴离子转运多肽1B1(OATP1B1[OATP-C],编码基因SLCO1B1)基因多态性对药代动力学和药效动力学的影响及其临床意义等方面的进展作一综述。     

Microstructures and mechanical properties of extruded Mg-1Mn-3.5Y and Mg-1Mn-1Y-2.5Nd alloys

Both Mg-1Mn-3.5Y and Mg-1Mn-1Y-2.5Nd alloys(mass fraction,%)were extruded at 380℃.Most of the(10 10) crystal planes in the Mg-1Mn-3.5Y alloy are parallel to the normal direction,while most of the(10 11)crystal planes in the Mg-1Mn-1Y-2.5Nd alloy are parallel to the normal direction.The tensile tests at room temperature,100℃ and 200℃ show that the Mg-1Mn-3.5Y alloy exhibits higher yield strength,but lower elongation to failure as compared with the Mg-1Mn-1Y-2.5Nd alloy. These differences in the tensile mechanical properties between the two alloys are mainly attributed to their different texture types and amount and distribution of the Mg24Y5 precipitates.The serration flow behavior is observed in the Mg-1Mn-1Y-2.5Nd alloy at 200℃,but does not occur in the Mg-1Mn-3.5Y alloy.The Mg-1Mn-3.5Y alloy shows the cleavage fracture mode,while the Mg-1Mn-1Y-2.5Nd alloy exhibits the dimple fracture mode.     

CYP1B1遗传多态性与个体化治疗

CYP1B1是细胞色素P450（cytochrome P450, CYP450s）家族成员,作为I相代谢酶,主要通过催化性激素、脂肪酸、维生素、褪黑素及外源性化学物质和药物的代谢,参与人体组织正常结构和生理功能的维持。研究发现,CYP1B1基因多态性会影响其蛋白表达水平和酶活性,对其催化的代谢过程产生影响,尤其是对性激素和外源物质的代谢过程的改变,与青光眼、各类癌症的发生发展及治疗密切相关。研究CYP1B1参与的机体代谢途径及基因多态性对其影响,有利于深入了解代谢途径的改变在相关疾病发生发展和药物治疗中的作用,加深对癌症、青光眼等疾病的认识,促进从基因层面检测和评估相关疾病的发生风险和预后,从而实现疾病的预防和早期发现,为个体化治疗提供依据,改善患者生存质量,延长生存期。本文拟就近五年CYP1B1参与的主要代谢途径及基因多态性对其影响的研究进展作一综述。     

La1-xSrxCo1-yFeyO3材料制备及结构分析

以溶胶-凝胶法制备La1-xSrxCo1-yFeyO3粉体，对粉体在不同温度热处理后的晶体结构进行XRD表征，详细研究粉体的成分组成以及发生的结构转变。结果表明，凝胶前驱体粉体颗粒比表面增大有利于钙钛矿结构晶相形成；合成粉体受前驱体比表面程度影响形成两种具有不同空间群钙钛矿结构晶相，并且各晶相元素化学计量比不相同，两相体系较稳定。     

Variability in Co2 Oxidation Resistance of 2 1/4 Cr 1 Mo and 1 Cr 1/2 Mo Steels

Abstract

Oxidation tests in CO₂ atmospheres on nominally identical casts of low alloy steels have revealed wide variation in oxidation resistance. A study has been made of the influence of chemical composition, mechanical and thermal treatment, and remelting on the CO₂ oxidation behaviour of steels of the 21/4 Cr 1 Mo and 1 Cr 1/2 Mo type.

Statistical analyses of CO₂ oxidation results have shown a strong positive correlation of oxidation rate with sulphur content in certain instances, but a number of anomalies have been found. A similar relationship has been obtained between ‘MnS’ content and oxidation rate by area count studies of the inclusions in a range of 2 1/4 Cr 1 Mo steels. These have also indicated a possible effect of ‘MnS’ particle size and particle size distribution which could account for some of the anomalous results obtained in the statistical work. Conventional solid state heat treatments appear to have no significant effect on the oxidation behaviour of 2 1/2 Cr 1 Mo and while remelting in argon did not generally improve oxidation behaviour, remelting in vacuo followed by forging and rolling resulted in a material of high oxidation resistance.