期刊文献+
共找到65篇文章
< 1 2 4 >
每页显示 20 50 100
Effect of minor Sc and Zr addition on microstructure and properties of ultra-high strength aluminum alloy 被引量:17
1
作者 张伟 邢远 +3 位作者 贾志宏 杨晓芳 刘庆 朱昌洛 《Transactions of Nonferrous Metals Society of China》 SCIE EI CAS CSCD 2014年第12期3866-3871,共6页
The Al-9Zn-2.8Mg-2.5Cu-xZr-ySc alloys (x=0, 0.15%, 0.15%; y=0, 0.05%, 0.15%), produced by low-frequent electromagnetic casting technology, were subjected to homogenization treatment, hot extrusion, solution and agin... The Al-9Zn-2.8Mg-2.5Cu-xZr-ySc alloys (x=0, 0.15%, 0.15%; y=0, 0.05%, 0.15%), produced by low-frequent electromagnetic casting technology, were subjected to homogenization treatment, hot extrusion, solution and aging treatment. The effects of minor Sc and Zr addition on microstructure, recrystallization and properties of alloys were studied by optical microscopy (OM), scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The results show that Sc and Zr addition can refine grains of the as-cast alloy by precipitation of primary Al3(Sc,Zr) particles formed during solidification as heterogeneous nuclei. Secondary Al3(Sc,Zr) precipitates formed during homogenization treatment strongly pin the movement of dislocation and subgrain boundaries, which can effectively inhibit the alloys recrystallization. Compared with the alloy without Sc and Zr addition, the Al-Zn-Mg-Cu-Zr alloy with 0.05%Sc and 0.15%Zr shows the increase in tensile strength and yield strength by 172 MPa and 218 MPa, respectively. Strengthening comes from the contributions of precipitation, substructure and grain refining. 展开更多
关键词 aluminum alloy low-frequent electromagnetic casting inhibit recrystallization primary Al3(Sc Zr) particles secondary Al3(Sc Zr) particles substructure strengthening precipitation strengthening grain refining
下载PDF
Genetic Analysis and Fine Mapping of Two Genes for Grain Shape and Weight in Rice 被引量:13
2
作者 Longbiao Guo Lilian Ma +6 位作者 Hua Jiang Dali Zeng Jiang Hu Liwen Wu Zhenyu Gao Guangheng Zhang Qian Qian 《Journal of Integrative Plant Biology》 SCIE CAS CSCD 2009年第1期45-51,共7页
To identify genetic loci controlling grain weight, an elite indica rice variety, Baodali, with large grains was identified and used in this study. Its derived F2, F3 and BC2 F2 with another japonica rice variety Zhong... To identify genetic loci controlling grain weight, an elite indica rice variety, Baodali, with large grains was identified and used in this study. Its derived F2, F3 and BC2 F2 with another japonica rice variety Zhonghua 11 were used as mapping populations. Linkage analyses demonstrated that two genes controlling grain weight, designated as GW3 and GW6, were mapped to chromosome 3 and chromosome 6, respectively. Fine mapping delimited GW3 to a 122 kb physical distance between two sequence tagged site markers (WGWt6 and WGW19) containing 16 open reading frames annotated by The Institute for Genomic Research (http://www.tigr.org). GW6 was further mapped between two simple sequence repeat markers (RM7179 and RM3187). These results are useful for both marker assisted selection of grain weight, and for further cloning of GW genes, which will contribute to the dissection of the molecular mechanism underlying grain weight in rice. 展开更多
关键词 fine mapping grain size marker assisted selection primary mapping rice.
原文传递
冷轧工艺对取向硅钢初次再结晶织构的影响 被引量:11
3
作者 王洋 许云波 +1 位作者 张元祥 王国栋 《东北大学学报(自然科学版)》 EI CAS CSCD 北大核心 2014年第2期217-222,共6页
研究了取向硅钢制备过程中常见的两种冷轧工艺,主要研究了一阶段冷轧与两阶段冷轧+中间退火工艺对初次再结晶组织及织构的影响.结果表明:采用两阶段冷轧+中间退火工艺制备以Cu2S为主抑制剂的取向硅钢,其初次再结晶平均晶粒尺寸为1... 研究了取向硅钢制备过程中常见的两种冷轧工艺,主要研究了一阶段冷轧与两阶段冷轧+中间退火工艺对初次再结晶组织及织构的影响.结果表明:采用两阶段冷轧+中间退火工艺制备以Cu2S为主抑制剂的取向硅钢,其初次再结晶平均晶粒尺寸为18.1μm,高斯晶粒的体积分数为0.6%,迁移性强的重位点阵晶界(∑5+∑9)和高能晶界(20°-45°取向偏差角)所占比例分别为1.8%和50.4%.与一阶段冷轧工艺相比,其初次再结晶晶粒较细,且高斯晶核与特征晶界所占的比例较高,有利于高斯晶粒发生二次再结晶. 展开更多
关键词 取向硅钢 冷轧工艺 初次再结晶 织构 晶界
下载PDF
Net Primary Productivity Increased on the Loess Plateau Following Implementation of the Grain to Green Program 被引量:10
4
作者 刘芳 闫慧敏 +2 位作者 顾峰雪 牛忠恩 黄玫 《Journal of Resources and Ecology》 CSCD 2017年第4期413-421,共9页
The spatio-temporal characteristics of net primary productivity(NPP) since implementation of the Grain to Green Program(GTGP) are important for understanding ecological restoration of the Loess Plateau in China. H... The spatio-temporal characteristics of net primary productivity(NPP) since implementation of the Grain to Green Program(GTGP) are important for understanding ecological restoration of the Loess Plateau in China. Here, we conduct spatio-temporal analysis of NPP using MODIS datasets(500 m, 8-day intervals) and VPM(Vegetation Photosynthesis Model) from 2000–2015. We found that NPP on the Loess Plateau increased significantly from 2000 to 2015(p0.05). Significant increases in NPP were observed in core areas of the GTGP, including northern Shaanxi and Lüliang Mountain in Shanxi. NPP in alluvial plains decreased due to urban expansion into cropland. Significant increases in NPP from 2006–2010 were located north of the area of change in 2000–2005. NPP increased across three vegetation types and four slope gradients. In hilly-gully regions prone to soil erosion, such as central and southeastern parts of the Loess Plateau, obvious vegetation restoration was detected. 展开更多
关键词 net primary productivity VPM grain to Green Program Loess Plateau
原文传递
热处理对含铝1.2367热作模具钢组织转变的影响 被引量:7
5
作者 胡艺耀 周健 +2 位作者 马党参 迟宏宵 苏杰 《材料热处理学报》 EI CAS CSCD 北大核心 2016年第4期183-189,共7页
利用OM,SEM,EDS和硬度测试等分析手段,研究了含铝1.2367钢热处理中退火组织及淬火组织转变规律,并利用Thermo-Calc软件对钢中合金相的变化规律进行了计算。结果表明:添加铝不改变1.2367钢平衡相的种类,但能提高钢的Ac1点,使α→γ转变... 利用OM,SEM,EDS和硬度测试等分析手段,研究了含铝1.2367钢热处理中退火组织及淬火组织转变规律,并利用Thermo-Calc软件对钢中合金相的变化规律进行了计算。结果表明:添加铝不改变1.2367钢平衡相的种类,但能提高钢的Ac1点,使α→γ转变的温度区间变宽;铝的添加在偏析严重区域引起了非平衡结晶产生了液析碳化物,同时减少了退火过程中合金碳化物析出的数量;当低温淬火时,铝的添加降低了淬火硬度,在Mo和V的复合作用下提高了碳化物的溶解温度,由于未溶碳化物的钉扎作用延缓了晶粒的粗化;进一步增加淬火温度,碳化物大量溶解,但由于偏析导致偏析带上的未溶碳化物分布不均匀,再加上部分氧化铝和氮化铝的作用,引起了混晶。 展开更多
关键词 热作模具钢 组织 液析碳化物 混晶
原文传递
合金结构钢原始组织对奥氏体形态的影响 被引量:5
6
作者 李智超 杨月君 《阜新矿业学院学报》 1989年第1期100-109,共10页
对不同原始组织的合金结构钢奥氏体形成过程进行了观察.结果发现,奥氏体形态有柱状、针状及羽毛状.原始组织对奥氏体形核及长大过程的影响十分敏感.
关键词 合金结构钢 奥氏体形态 起始晶粒
下载PDF
Impact of Commercial Organic Ameliorants on Nitrogen and Phosphorus Concentrations of Maize Biomass at Ninth Leaf and Silking Growth Stages
7
作者 Tlangelani Cedric Baloyi Funso Raphael Kutu Christiaan Cornelius du Preez 《Journal of Geoscience and Environment Protection》 2023年第5期102-125,共24页
The response of grain yield, biomass yield and harvest index of maize to the application of commercial organic ameliorants was inconsistent and poor. Hence it was hypothesized that the supply of N and P to maize plant... The response of grain yield, biomass yield and harvest index of maize to the application of commercial organic ameliorants was inconsistent and poor. Hence it was hypothesized that the supply of N and P to maize plants was inadequate during vegetative growth, resulting in low concentrations of the two nutrients in maize biomass. The effects of nine ameliorants on the N and P concentrations of maize plants at ninth leaf (V9) and silking (R1) stages of maize were studied over three years at Bothaville (8% clay), Ottosdal (12% clay) and Potchefstroom (34% clay). All ameliorants were applied as prescribed by manufacturers. The N and P concentrations in maize biomass of the ameliorants at V9 and R1 were lower, comparable or higher, showing that the inconsistent and poor response of yield parameters can not be ascribed to inadequate uptake of N and P. A matter of concern that justifies thorough investigation, is the prescribed use of Crop care and Growmor with partial and of Montys and Promis with no NPK fertilization, an unsustainable practice over the long term. Characterization of the active ingredient(s) of the ameliorants is deemed also of importance for better insight. 展开更多
关键词 Field Trials grain Yield primary Nutrients Reproductive Growth Vegetative Growth
下载PDF
5182铝合金汽车板的高温快速退火 被引量:5
8
作者 胡传彬 黄程毅 +1 位作者 任月路 赖仕祯 《金属热处理》 CAS CSCD 北大核心 2016年第9期138-141,共4页
通过模拟气垫式退火炉的高温快速退火工艺,研究了退火温度、保温时间对5182铝合金冷轧板力学性能、显微组织和拉胀成形性的影响。结果表明,高温快速退火可使5182冷轧板瞬时完成初次再结晶,得到平均尺寸11~13μm的细小晶粒,较高的退火... 通过模拟气垫式退火炉的高温快速退火工艺,研究了退火温度、保温时间对5182铝合金冷轧板力学性能、显微组织和拉胀成形性的影响。结果表明,高温快速退火可使5182冷轧板瞬时完成初次再结晶,得到平均尺寸11~13μm的细小晶粒,较高的退火温度可缩短完成再结晶所需的时间,为控制晶粒发生异常长大,退火温度不宜超过480℃,保温时间不宜超过3 min,退火板伸长率可达26.5%,杯突值达9.5 mm。 展开更多
关键词 5182铝合金冷轧板 高温快速退火 初次再结晶 晶粒长大 拉胀成形
原文传递
A357半固态初生相在二次加热和成形过程中的演变行为 被引量:5
9
作者 王建甫 杨弋涛 +1 位作者 张恒华 邵光杰 《特种铸造及有色合金》 CAS CSCD 北大核心 2008年第3期189-192,共4页
为了认识半固态成形微观组织形貌的演变规律,较为系统地了解初生α相的演变和充型行为,对A357半固态铝合金坯料进行了二次加热和压铸成形试验,用量化的方法分析了它们的组织特征。发现二次加热过程中,初生相随着加热温度的上升和时间的... 为了认识半固态成形微观组织形貌的演变规律,较为系统地了解初生α相的演变和充型行为,对A357半固态铝合金坯料进行了二次加热和压铸成形试验,用量化的方法分析了它们的组织特征。发现二次加热过程中,初生相随着加热温度的上升和时间的延长,出现了合并、长大和球化;在充型过程中,粗大的α相晶粒容易在拐角和浇口处发生聚集,液相较多的地方容易产生比较多的细小α晶粒。 展开更多
关键词 初生相 晶粒合并 感应加热 半固态成形 A357合金
下载PDF
清洗质量对取向硅钢初次晶粒的影响
10
作者 程迪夫 程祥威 +5 位作者 曾剑 王雄奎 赵胜利 蒋杰 杨朝 金犁 《电工钢》 CAS 2023年第3期24-27,共4页
研究了不同清洗工艺对取向硅钢清洗质量的影响,不同的清洗质量对应不同的初次晶粒尺寸和成品磁性能。结果表明,随着清洗液浓度的增加、温度的提升和时间的延长,钢板表面清洗质量得到改善;清洗质量的差异会导致钢板初次晶粒均匀性发生变... 研究了不同清洗工艺对取向硅钢清洗质量的影响,不同的清洗质量对应不同的初次晶粒尺寸和成品磁性能。结果表明,随着清洗液浓度的增加、温度的提升和时间的延长,钢板表面清洗质量得到改善;清洗质量的差异会导致钢板初次晶粒均匀性发生变化,清洗质量好的钢带,初次晶粒均匀并且成品磁性能优良。 展开更多
关键词 取向硅钢 脱碳退火 清洗质量 初次晶粒
下载PDF
Pollination dynamics, grain weight and grain cell number within the inflorescence and spikelet in oat and wheat
11
作者 Ari Rajala Pirjo Peltonen-Sainio 《Agricultural Sciences》 2011年第3期283-290,共8页
Oat (Avena sativa L.) and wheat (Triticum aestivum L.) vary in the structure of their inflores-cences and also in how pollination proceeds within the inflorescence. In both species the grain position in the spikelet d... Oat (Avena sativa L.) and wheat (Triticum aestivum L.) vary in the structure of their inflores-cences and also in how pollination proceeds within the inflorescence. In both species the grain position in the spikelet determines grain weight potential. Primary grains in oat and proximal grains in wheat weigh more than secondary and distal grains. This variation in grain weight can potentially result from differences in post-pollination cell division in the grain. In this study pollination duration and dynamics were analyzed from head samples collected at two-day intervals, starting from the pollination of the most advanced floret. The number of grain cells was determined for individual grains throughout the inflorescence, starting from the pollination event. When mature, grain position in the spikelet and spike was noted and grain weight assessed. Pollination advance in oat proceeded from the uppermost primary floret towards the basal spikelets in ten to eleven days. Within the spikelet, the primary floret was pollinated on average one day earlier than the secondary floret. In wheat, pollination duration was four to five days, starting from the proximal florets in the mid-section of the inflorescence progressing towards the apical and basal spikelets. Proximal florets were pollinated one to two days earlier than distal florets. Maximum cell number in primary grains exceeded that of secondary grains in two oat cultivars. Similarly, primary grains were heavier than secondary grains. Cell number and single grain weight were correlated in terms of grain position in the spikelet (primary – secondary) and cultivar. Oat cultivar Belinda had a higher single grain weight than Fiia, which was also expressed as larger grain cell number. In wheat, proximal grains had higher maximum cell numbers and were also heavier than distal grains. This grain weight gradient was apparent throughout the inflorescence. Consequently, grain cell number is one of the possible regulators of grain-filling capacity in both cereal crops. 展开更多
关键词 CELL Number Distal grain Filling Potential Floret OAT POLLINATION primary grain Proximal grain Secondary grain WHEAT Cell-PLoc Signal-CF Signal-3L
下载PDF
我国部分省区储粮场所中主要害虫发生分布调查及其防治重点 被引量:4
12
作者 王殿轩 谭永清 +5 位作者 白春启 姜碧若 张浩 李慧 唐培安 邵小龙 《河南工业大学学报(自然科学版)》 CAS 北大核心 2018年第2期93-97,共5页
为科学有效地防治储粮主要害虫,通过对中国11省81地市480个代表性储粮场所现场采集,调查了的储粮"主要害虫"谷蠹、大谷盗、印度谷蛾、麦蛾、玉米象、米象、咖啡豆象、绿豆象、豌豆象、蚕豆象的发生分布情况,结合害虫种类及其... 为科学有效地防治储粮主要害虫,通过对中国11省81地市480个代表性储粮场所现场采集,调查了的储粮"主要害虫"谷蠹、大谷盗、印度谷蛾、麦蛾、玉米象、米象、咖啡豆象、绿豆象、豌豆象、蚕豆象的发生分布情况,结合害虫种类及其习性提出了科学防治的重点。调查发现玉米象、印度谷蛾、麦蛾、大谷盗在所调查省区内均有分布,米象和谷蠹为部分省区分布。山西省、山东省和河南省共28个地市中有20个发现谷蠹,湖北省、湖南省、浙江省、福建省、广东省、云南省、海南省等全部44个调查地市均发现谷蠹。广东省、云南省、福建省、湖南省等原有米象分布记录的省份本次全部采集到了此种害虫,新增加了米象在浙江省、湖北省、河南省、山东省等的分布记录,采集到米象的地市包括浙江省的宁波市、湖州市、台州市、温州市、金华市和湖北省的恩施州、咸宁市、武汉市、麻城市、荆州市、荆门市等,河南省17个调查地市中有米象的地市包括南阳市、平顶山市、洛阳市、漯河市、周口市、商丘市,山东省调查的菏泽市、日照市、青岛市、烟台市、聊城市、济南市、临沂市中只有青岛市采集到米象。谷物储藏场所的"主要害虫"以玉米象、米象、谷蠹、印度谷蛾、麦蛾为主,大谷盗多发生于粮食加工厂等非原粮存粮场所,咖啡豆象、绿豆象、蚕豆象偶有发现,未发现豌豆象。谷物储藏中需重点防控蛀食性、隐蔽发生、危害严重的玉米象、米象、谷蠹等,防治工作注意隐蔽性害虫检测和诱捕控制技术的应用。 展开更多
关键词 主要害虫 储粮场所 调查 防治
下载PDF
改进共沉淀法以提高三效催化剂中铈锆复合氧化物的热稳定性(英文) 被引量:4
13
作者 伍青峰 崔亚娟 +4 位作者 张海龙 周怡 兰丽 王健礼 陈耀强 《无机材料学报》 SCIE EI CAS CSCD 北大核心 2017年第3期331-336,共6页
采用共沉淀法制备了铈锆材料(铈锆比为3/2)。通过改进反应器装置(图1),延长了初始晶粒生长的时间,提高了铈锆材料的热稳定性。采用X射线衍射(XRD)、氮气吸脱附和透射电镜(TEM)对制备的材料进行了表征。结果表明,延长初始晶粒生长的时间... 采用共沉淀法制备了铈锆材料(铈锆比为3/2)。通过改进反应器装置(图1),延长了初始晶粒生长的时间,提高了铈锆材料的热稳定性。采用X射线衍射(XRD)、氮气吸脱附和透射电镜(TEM)对制备的材料进行了表征。结果表明,延长初始晶粒生长的时间可以得到较大尺寸的晶粒,这有利于提高材料的织构和结构性能,从而提高热稳定性。本研究将该材料应用于单Pd三效催化剂,表现出了优异的活性和热稳定性,具有良好的应用前景。 展开更多
关键词 铈锆材料 初始晶粒 共沉淀法 热稳定性
下载PDF
Microstructure evolution and mechanical properties of heat treated LCB titanium alloy 被引量:4
14
作者 Khaled M. IBRAHIM Mansour MHAEDE Lothar WAGNER 《Transactions of Nonferrous Metals Society of China》 SCIE EI CAS CSCD 2012年第11期2609-2615,共7页
The influence of ageing time on microstructure and mechanical properties of low-cost beta (LCB) titanium alloy with a chemical composition of Ti-6.6Mo-4.5Fe-1.5Al was investigated. The correlation between microstruc... The influence of ageing time on microstructure and mechanical properties of low-cost beta (LCB) titanium alloy with a chemical composition of Ti-6.6Mo-4.5Fe-1.5Al was investigated. The correlation between microstructure and fatigue crack initiation and growth was also studied. Increasing ageing time tended to increase the volume fraction of the secondary α-precipitates, β-grain size and partial spheroidization of primary α-phase. The maximum tensile strength (1565 MPa) and fatigue limit (750 MPa) were obtained for the samples aged at 500 °C for 0.5 h, while the minimum ones of 1515 MPa and 625 MPa, respectively, were reported for the samples aged at 500 °C for 4 h. The samples aged at 500 °C for 4 h showed a transgranular fracture mode. However, the samples aged at 500 °C for 0.5 h revealed a mixture fracture mode of transgranular and intergranular. The formed cracks on the outer surface of the fatigue samples were found to propagate through the β-grains connecting the primary α-particles existing at the β-grain boundaries. 展开更多
关键词 beta Ti alloy Ti-6.6Mo-4.5Fe-1.5Al alloy fatigue crack ageing secondary α primary α β-grain tensile strength fatigue limit
下载PDF
Morphologically templated nucleation of primary Si on AlP in hypereutectic Al-Si alloys 被引量:2
15
作者 Xiangzhen Zhu Shihao Wang +2 位作者 Xixi Dong Xiangfa Liu Shouxun Ji 《Journal of Materials Science & Technology》 SCIE EI CAS CSCD 2022年第5期36-45,共10页
AlP has been widely used as an effective heterogenous nucleus for primary Si phase in hypereutectic AlSi alloys,but the morphological correlation between AlP and primary Si is still confusing.In the present work,the m... AlP has been widely used as an effective heterogenous nucleus for primary Si phase in hypereutectic AlSi alloys,but the morphological correlation between AlP and primary Si is still confusing.In the present work,the morphologies of AlP crystals were studied comprehensively by experimental observation and theorical prediction.It is found that AlP collected from an Al-0.03 P melt could be divided into two categories:spinel twin crystals and non-twin crystals.During the nucleation process,these two kinds of AlP crystals triggered morphologically templated nucleation of primary Si phase,resulting in the formation of hexagonal primary Si twin and octahedral non-twin crystals,respectively.As such,the percentage of primary Si twin crystals in the experimental Al-18 Si alloy was also increased obviously after the morphologically templated nucleation via Al P.The morphologically templated nucleation also eliminated the dendritic growth of primary Si phase and the formation of hopper structures inside primary Si,forcing primary Si to maintain to be faceted solid crystals through layer-by-layer growing mechanism.The insight into morphologically templated nucleation offers a new view in understanding the mechanism of heterogeneous nucleation of primary Si phase on AlP nuclei. 展开更多
关键词 Aluminium alloys SOLIDIFICATION NUCLEATION primary Si grain refinement Morphology
原文传递
脉冲磁场下冷轧取向硅钢的初次再结晶研究 被引量:2
16
作者 马涛 黄军军 李莉娟 《材料导报》 EI CAS CSCD 北大核心 2012年第12期46-48,69,共4页
研究了脉冲磁场对冷轧取向硅钢热处理过程中初次再结晶组织形成规律的影响。通过分析冷轧硅钢在不同热处理条件下初次再结晶晶粒长大的动力学可知,施加脉冲磁场能够抑制晶粒的再结晶及正常晶粒长大,而且沿法向施加脉冲磁场抑制晶粒长大... 研究了脉冲磁场对冷轧取向硅钢热处理过程中初次再结晶组织形成规律的影响。通过分析冷轧硅钢在不同热处理条件下初次再结晶晶粒长大的动力学可知,施加脉冲磁场能够抑制晶粒的再结晶及正常晶粒长大,而且沿法向施加脉冲磁场抑制晶粒长大的作用最大。脉冲磁场作用下可用异速生长幂函数建立基体晶粒的生长动力学模型。 展开更多
关键词 取向硅钢 脉冲磁场退火 初次再结晶 晶粒长大 电子背散射衍射
下载PDF
The evolution of microstructure and mechanical properties during high-speed direct-chill casting in different Al–Mg_2Si in situ composites 被引量:1
17
作者 Dong-tao Wang Hai-tao Zhang +3 位作者 Lei Li Hai-lin Wu Ke Qin Jian-zhong Cui 《International Journal of Minerals,Metallurgy and Materials》 SCIE EI CAS CSCD 2018年第9期1080-1089,共10页
The effect of high-speed direct-chill(DC) casting on the microstructure and mechanical properties of Al–Mg_2Si in situ composites and AA6061 alloy was investigated. The microstructural evolution of the Al–Mg_2Si com... The effect of high-speed direct-chill(DC) casting on the microstructure and mechanical properties of Al–Mg_2Si in situ composites and AA6061 alloy was investigated. The microstructural evolution of the Al–Mg_2Si composites and AA6061 alloy was examined by optical microscopy, field-emission scanning electron microscopy(FE-SEM) and transmission electron microscopy(TEM). The results revealed that an increase of the casting speed substantially refined the primary Mg_2Si particles(from 28 to 12 μm), the spacing of eutectic Mg_2Si(from 3 to 0.5 μm), and the grains of AA6061 alloy(from 102 to 22 μm). The morphology of the eutectic Mg_2Si transformed from lamellar to rod-like and fibrous with increasing casting speed. The tensile tests showed that the yield strength, tensile strength, and elongation improved at higher casting speeds because of refinement of the Mg_2Si phase and the grains in the Al–Mg_2Si composites and the AA6061 alloy. High-speed DC casting is demonstrated to be an effective method to improve the mechanical properties of Al–Mg_2Si composites and AA6061 alloy billets. 展开更多
关键词 Al–Mg2Si in SITU composite CASTING speed grain size primary MG2SI mechanical property
下载PDF
超声波搅拌对ZA27合金组织的影响 被引量:2
18
作者 莫立娥 程和法 +2 位作者 李拥军 项苹 张章 《特种铸造及有色合金》 CAS CSCD 北大核心 2007年第S1期148-150,共3页
在ZA27合金熔体中导入超声波搅拌能够获得成分均匀、晶粒细小的半固态ZA27合金浆料,本文研究了超声波开始导入时的熔体温度(即熔体过热度)和搅拌时间对ZA27合金初生相尺寸、形貌和分布形态的影响。结果表明,随着超声波开始导入时熔体过... 在ZA27合金熔体中导入超声波搅拌能够获得成分均匀、晶粒细小的半固态ZA27合金浆料,本文研究了超声波开始导入时的熔体温度(即熔体过热度)和搅拌时间对ZA27合金初生相尺寸、形貌和分布形态的影响。结果表明,随着超声波开始导入时熔体过热度的增加,初生相的细化效果大幅度地降低;随着超声波搅拌时间的增加,会得到一个初生相最细小、圆整、分布最均匀的时间点,随后随搅拌时间的延长,初生相晶粒会出现聚集、长大;超声波搅拌能减少晶粒的聚集,使其分布更均匀。 展开更多
关键词 超声波搅拌导入时熔体温度 超声波搅拌时间 等温搅拌 ZA27合金 初生相 晶粒细化
下载PDF
取向硅钢常化脱碳的工艺研究 被引量:1
19
作者 田文洲 王若平 方泽民 《武汉工程职业技术学院学报》 2010年第1期9-10,13,共3页
利用常化预脱碳一次冷轧法实验生产出0.23mm HIB,侧重研究热轧板经平整压下后,不同的常化时预脱碳工艺对预脱碳量的影响。讨论了采用常化脱碳工艺获得的热轧板组织与常规0.23mm HIB常化组织的差别。
关键词 取向硅钢 常化脱碳 脱碳量 平整压下 初次晶粒
下载PDF
Distribution of Rice Grains on Panicle Axis and Its Relationship with Seed-Setting Ability in Liaoning, China
20
作者 XU Zheng-jin CHEN Wen-fu SHUN Zhan-hui ZHANG Shu-lin LIU Li-xia ZHOU Shu-qing 《Agricultural Sciences in China》 CAS CSCD 2006年第3期202-208,共7页
Studies were conducted with rice varieties developed in recent years in Liaoning Province of China as test materials. Results showed that the varieties tested could be divided into three types: (1) the high-yieldi... Studies were conducted with rice varieties developed in recent years in Liaoning Province of China as test materials. Results showed that the varieties tested could be divided into three types: (1) the high-yielding (HYV), (2) the mediumyielding (MYV), and (3) the low-yielding (LYV). The panicle population was in the order of HYV〈 MYV 〈 LYV, while the grain number per panicle and seed-setting rate were just opposite. There was no significant difference in the 1 000-grain weight. Biomass was higher in HYV than in MYV and LYV, while the harvest index was higher in HYV and MYV than in LYV. Yield was inversely correlated with panicle population, but positively correlated with the grain number per panicle, seed-setting rate, the number of primary and secondary branch grains, seed density and harvest index. Yield was most closely linked with the grain number per panicle which was determined chiefly by the number of secondary branch grains and to a lesser degree by seed density and the number of primary branch grains. The seed-setting rate of the secondary branches was positively correlated with that of the whole panicle and yield. The peak value of primary branches for HYV, MYV and LYV was 12-14, 10-13 and 8-12, respectively. LYV had fewer secondary branch grains, while MYV and HYV had more. Such grains distributed mainly in the middle and lower parts of panicle axis for LYV and in the middle and upper parts for MYV and HYV. 展开更多
关键词 rice grain distribution primary branch secondary branch seed-setting ability
下载PDF
上一页 1 2 4 下一页 到第
使用帮助 返回顶部