基于三种干旱指标的朝阳市干旱特征分析

旱灾具有出现频率高、持续时间长、波及范围广等特点，本文运用降水距平百分率、Z指数、SPI标准化降水指数，对朝阳地区50a（1969～2018）干旱特征进行分析。结果表明：Z指数与SPI标准化降水指标得到的朝阳地区干旱特征情况基本一致，能较好地反映出该地区的干旱特征，朝阳地区1969～2018年自然灾害频繁发生，严重干旱年份主要集中在1980、1981、1982 年，与实际相符。     

Mixed phase bioceramics in the CaMgSi2O6 – MoO3 system: Mechanical properties and in-vitro bioactivity

Mixed phase materials in the quasi binary diopside (CaMgSi₂O₆) – molybdite (MoO₃) system were synthesized by a precipitation method. Materials were fabricated with diopside to molybdite ratios of 1:0, 10:1, 5:1, 2:1 and 1:1. XRD, SEM and EDS results show that alongside the initial diopside phase, phases such as calcium molybdate CaMoO₄, rod-like enstatite MgSiO₃ and cristobalite SiO₂ formed as the molybdite content increased, and diopside was entirely absent at the highest molybdite content. At lower Mo content, mixed phase materials showed higher hardness and slower biodegradation in SBF relative to pristine diopside, while maintaining reasonable hydroxyapatite (HAp) formation capability. In contrast, materials with higher molybdite content exhibited lower hardness and bioactivity. The variation in the mechanical and bioactive performance could be attributed to the presence of bulk CaMoO₄, acting as a reinforcement, and rod-like MgSiO₃ with a highly porous and fragile structure. The trend of hardness is not consistent to the proportion of the component phases could be attributed to morphologies, interfaces, and densities of the samples. Both of secondary phases had poorer HAp deposition compared to pure diopside, indicating the MoO₃ addition lowered mixed phase CaMgSi₂O₆ – MoO₃ bioceramics’ ability to form Hap. The results suggest that moderate addition of molybdite to diopside would be an effective pathway towards crystalline bioceramics with enhanced performance.     

镍基高温合金GH202高温氧化后的微观组织演变

研究了镍基高温合金GH202在800~1100 ℃高温氧化后晶粒、碳化物和强化相的演变过程。采用透射电子显微镜、扫描电子显微镜和电子背散射衍射对其微观结构进行了表征。结果表明：镍基高温合金的硬度随氧化温度的升高而降低，1100 ℃氧化100 h后，硬度降低了43.5%。800和900 ℃氧化后晶粒生长速度较慢，而经900 ℃氧化后晶界碳化物析出显著增加。在1000和1100 ℃氧化后，晶粒尺寸明显增大。氧化过程中晶界迁移是由晶界两侧自由能差决定，温度越高，晶界向曲率中心迁移越快，大量细小晶粒被吞并形成了大晶粒。大块状碳化物（MC）分解成大量的碳原子，与Cr原子结合形成少量的富Cr颗粒状M₂₃C₆。在900 ℃氧化150 h后，M₂₃C₆演化为富Ti的M₆C。随着氧化温度的升高，碳化物在γ相中回熔。在800、900和1000 ℃氧化后，γ′相逐渐长大，在1100 ℃氧化100 h后，完全溶解于γ相。     

碱铝硅酸盐玻璃化学强化关键影响因素概述

化学强化是一种玻璃机械强度增强方法,适用于异型、超薄、高碱、高膨胀玻璃增强,因新型超薄显示产品的屏幕保护玻璃发展需要,化学强化技术重新在碱铝硅酸盐玻璃品种掀起研究热潮。本文对化学强化本质及铝硅酸盐玻璃在屏幕保护玻璃应用进行了回顾,基于玻璃化学强化的高CS、DOL和低CT诉求,归纳总结了关键影响因素,第1,碱铝硅酸盐玻璃的成分及结构是基础,氧化铝有利玻璃网络孔隙增大创造交换通道,氧化钠或氧化锂是离子交换关键物质;第2,对于玻璃组成和结构设计,要求玻璃网络键合度R=O/Si或O/(Si+Al)满足2.15~2.40,碱金属氧化物质量分数大于13%且膨胀系数大于6×10^-6/℃;第3,在化学强化工艺方面,化学强化温度决定离子扩散系数,化学强化时间决定DOL,一步法仅能获得相对较大的CS,而DOL不很理想,只有两种离子参与交换的二步法才有利于CS和DOL同步提高。     

ZK60镁合金表面滚压强化试验研究

试验研究了ZK60镁合金表面滚压加工中工艺参数对试件表面粗糙度、表面形貌、表面残余应力和表层显微硬度的影响,结果表明滚压力和重复滚压次数对试件的表面粗糙度、表面形貌以及表面残余应力和表层硬度影响程度较大,滚压速度影响较小。对精车ZK60镁合金试件进行滚压加工,试件表面粗糙度R a、R z最大减小了50.3%和48.1%;残余压应力最大可达-54.55 MPa;显微硬度从试件表层到内部基体材料逐渐降低,表层硬度值最大为92.83 HV 0.25,比基体材料硬度提高了15.32%。     

High-temperature behavior of oxide dispersion strengthening CoNiCrAlY

To fabricate oxide dispersion strengthened bond coatings, commercial Co–30wt-%Ni–20Cr–8Al–0?4Y powder was milled with 2% additions of Al₂O₃, Y₂O₃ or Y₂O₃ + HfO₂. Low-pressure plasma sprayed, free-standing specimens were oxidised in air + 10%H2O at 1100 °C both isothermally (100 h) and in 500, 1?h cycles. Dry air cyclic testing conducted at both ORNL and FZJ showed remarkably similar results. In general, the water vapour addition caused more scale spallation. Two LPPS specimens without oxide additions were tested for comparison. The specimens with 2%Al₂O₃ addition exhibited the best behaviour as the powder already contained 0?4%Y. Additions of 2%Y₂O₃ and especially 1%Y₂O₃ + 1%HfO₂ resulted in over-doping as evidenced by high mass gains and the formation of Y- and Hf-rich pegs. Scanning transmission electron microscopy of the isothermal specimens showed no Hf and/or Y segregation to the alumina scale grain boundaries in the over-doped specimens.     

氮对镀锡钢板的强化作用

通过物理化学相分析研究了3种不同氮含量镀锡板中固溶氮、化合氮的含量,结合相关理论计算了镀锡板中氮的固溶强化和析出强化对强度的贡献。结果表明:随着总氮含量从0.0021%提高到0.0103%,钢中化合氮含量下降10.1%,但是AlN析出相中的氮的含量上升10.7%。氮在提高镀锡板强度方面发挥重要作用,钢中总氮含量提高0.0082%,其对屈服强度的贡献值提升约30 MPa。     

X80钢JCOE制管过程应变强化规律及其影响因素研究

为了探究X80钢制管过程中应变强化规律及其影响因素，采用厚度22 mm不同厂家生产的6种X80热轧钢板，以相同的JCOE制管工艺生产出 Φ1 219 mm×22 mm规格钢管，并对6种钢板的拉伸性能以及钢板、钢管拉伸性能差异进行了检测。根据检测结果，从化学成分、显微组织等方面分析了制管前后拉伸性能变化的影响因素。分析结果显示，X80钢制管后屈服强度、屈强比有较大幅度的升高，不同材料的升高幅度不同。研究表明，拉伸性能的变化与合金成分无明显的规律，主要与显微组织有关。     

砂土内微生物诱导碳酸钙结晶的检测方法研究

为了寻找砂土中微生物诱导碳酸钙结晶(MICP)过程的无损检测方法,采用3种粒径的砂子和两种浓度的胶结溶液进行了砂土的胶结试验,检测了砂土流出液的流量、p H值、尿素浓度和Ca2+浓度等化学指标变化情况,并对碳酸钙晶体的生成数量和分布进行了分析。试验结果显示:砂土流出液的流量和Ca2+浓度能够预测MICP过程中碳酸钙晶体的生成数量,p H值和尿素浓度能够预测MICP过程中尿素的水解程度;砂土中碳酸钙晶体的生成数量与注入的Ca2+总量呈现线性增长的关系,其线性系数可以通过砂土的粒径和胶结溶液的浓度表示,胶结后砂柱的碳酸钙分布并不均匀,小粒径的砂柱上部碳酸钙含量较高,而大粒径的砂柱下部碳酸钙含量较高。