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Effect of heat treatment on mechanical properties and microstructure evolution of Mg-9.5Gd-4Y-2.2Zn-0.5Zr alloy

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Journal of Magnesium and Alloys 2022年第4期10卷 1124-1132页

作者： Jie Zheng zhaoming yan Jinsheng Ji Yusha Shi Heng Zhang Zhimin Zhang Yong Xue School of Materials Science and Engineering North University of ChinaTaiyuan 030051China

Regarding the as-cast Mg-9.5Gd-4Y-2.2Zn-0.5Zr alloy,the effect of heat treatment on its properties at room temperature(RT),as well as the mechanical properties and microstructure evolution of various peak-aging samples at different tensile temperatures were discussed in this *** results indicated that the optimal heat treatment process of the alloy was:520℃×24 h+200℃×112 *** this condition,the yield strength(YS),ultimate tensile strength(UTS)and elongation(EL)at RT were:238 MPa,327 MPa and 2.5%,*** the tensile temperature increases,the strength increases firstly and then decreases,but the ductility increases *** microstructures evolution of 200℃ peak-aging(200PA)and 250℃ peak-aging(250PA)samples were different with the increasing tensile *** tensile test processed at 150℃,the denseβ’phase and rod-shaped basalγ’phase will be formed in the 200PA ***,at 300℃,theβ’phases ***β’and LPSO phases in the 250PA sample coarsened gradually as the tensile temperature increased,and 14H-LPSO phases were formed during tensile at 300℃.The 200PA sample reached the highest strength when tensile at 150℃,which was attributed to the hindrance of the basal dislocation and non-basal dislocation slip by the prismaticβ’phases and the newly formed basalγ’precipitates.

关键词： Mg-Gd-Y-Zn-Zr alloy Heat treatment Elevated temperature mechanical properties Microstructure evolution

Dietary supplementation with betaine or glycine improves the carcass trait,meat quality and lipid metabolism of finishing mini-pigs

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Animal Nutrition 2021年第2期7卷 376-383页

作者： Yinzhao Zhong zhaoming yan Bo Song Changbing Zheng Yehui Duan Xiangfeng Kong JinPing Deng Fengna Li Guangdong Provincial Key Laboratory of Animal Nutrition Regulation South China Agricultural UniversityGuangzhou 510642China Hunan Provincial Key Laboratory of Animal Nutritional Physiology and Metabolic Process Changsha 410125China Key Laboratory of Agro-ecological Processes in Subtropical Region Institute of Subtropical AgricultureChinese Academy of SciencesChangsha 410125China Hunan Provincial Engineering Research Center for Healthy Livestock and Poultry Production Changsha 410125China National Engineering Laboratory for Pollution Control and Waste Utilization in Livestock and Poultry Production Changsha 410125China Scientific Observing and Experimental Station of Animal Nutrition and Feed Science in South-Central Ministry of AgricultureChangsha 410125China University of Chinese Academy of Sciences Beijing 100039China College of Animal Science and Technology Hunan Agricultural UniversityChangsha 410128China

The objective of the study is to evaluate and compare the effects of betaine or glycine on carcass trait,meat quality and lipid metabolism of finishing Huan Jiang *** called trimethylglycine is a methyl derivative of glycine,but few researches were conducted to compare the impact of dietary betaine and glycine on *** hundred and forty-four Huan Jiang mini-pigs(body weight=10.55±0.15 kg;70 d)were randomly divided to 3 treatment groups(basal diet,glycine or betaine).Results indicated that dietary betaine increased the average daily gain(ADG)and final weight(P<0.05).Dietary glycine or betaine markedly reduced average backfat thickness(P<0.05)and heightened lean percentage(P<0.01)compared to the control ***,in comparison with the control group,betaine significantly improved the redness(a*)and tenderness(shear force)of the longissimus dorsi(LD)muscle(P<0.05),whereas glycine only raised the value of a*of the LD muscle(P<0.05).These results showed that diet supplemented with 0.25%betaine and equimolar amounts of glycine could regulate cascass trait and meat quality of finishing Huan Jiang mini-pigs,and the effect of betaine was superior to that of glycine.

关键词： Betaine Glycine Meat quality Lipid metabolism Huan jiang mini-pig

Microstructure evolution,texture and mechanical properties of a Mg-Gd-Y-Zn-Zr alloy fabricated by cyclic expansion extrusion with an asymmetrical extrusion cavity:The influence of passes and processing route

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Journal of Magnesium and Alloys 2021年第3期9卷 964-982页

作者： zhaoming yan Xubin Li Jie Zheng Zhimin Zhang Qiang Wang Kaihua Xu Hongzhi Fan Guanshi Zhang Jiaxuan Zhu Yong Xue School of Materials Science and Engineering North University of ChinaTaiyuan 030051China College of Mechatronics Engineering North University of ChinaTaiyuan 030051China

In the present work,two processing routes(A and B)with 3 CEE-AEC passes are performed on Mg-13 Gd-4 Y-2 Zn-0.4 Zr alloys,and the resultant microstructure evolution,texture analysis and mechanical properties are investigated *** core difference between the two processing routes is the orientation between the expansion and extrusion steps,i.e.,they are parallel to each other for on route A and perpendicular to each other for route *** results show that a remarkable grain refinement is achieved via both processing routes due to dynamic recrystallization(DRX).Fine equiaxed grains are observed in the samples processed with route B with a final size of 3.6±0.4μm compared to the grain size of 4.5±0.5μm with route *** an increasing number of CEE-AEC passes,the overall texture intensity decreases,and the basal texture gradually changes to the mixed texture *** shear deformation introduced by the asymmetrical extrusion cavity promotes a broad angular distribution of the basal planes on routes A and B,leading to an obvious increase in the Schmid factor for the activation of the basal a slip *** tensile test at ambient temperature reveals that the comprehensive mechanical properties are improved,and the conventional mechanical anisotropy of as-received alloys is alleviated by successive CEE-AEC processing,which is mainly derived from the competitive balance relation between the grain refinement and texture modification.

关键词： CEE-AEC Mg-Gd-Y-Zn-Zr Microstructure Texture Mechanical properties

旋转反挤压与常规反挤压Mg-Gd-Y-Zn-Zr合金杯形件显微组织对比研究

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稀有金属材料与工程 2024年第9期53卷 2653-2660页

作者：徐健乔为栋闫钊鸣薛勇中北大学材料科学与工程学院山西太原030051

使用传统反挤压(conventional backward extrusion,CBE)和旋转反挤压(rotational backward extrusion,RBE)2种工艺制备了不同的Mg-9Gd-4Y-2Zn-0.5Zr(质量分数,%)合金杯形件。使用OM、SEM、EBSD等测试方法对不同杯形件的对应区域进行表征。结果表明:RBE的晶粒细化能力远远大于CBE,RBE心部的晶粒细化效果最好,RBE-Ⅲ区域的动态再结晶(dynamic recrystallization,DRX)含量可达98.1%,平均晶粒尺寸为2.5μm。RBE的织构弱化能力也优于CBE,心部的织构强度可弱化为1.258。在RBE得到杯形件当中,其长周期堆积有序相(LPSO)相的破碎程度也大于CBE,第二相(β相)分布得也更加均匀,析出的β相可以通过粒子刺激形核(particles simulated nucleation,PSN)机制促进DRX,并通过钉扎效应抑制晶粒长大。在CBE和RBE杯形件成形过程中,其动态再结晶机制相同,为连续动态再结晶(continuous dynamic recrystallization,CDRX)和不连续动态再结晶(discontinuous dynamic recrystallization,DDRX)2种。

关键词：旋转反挤压杯形件 Mg-Gd-Y-Zn-Zr合金动态再结晶 LPSO相

单面螺纹抽钉干涉配合复合材料连接件挤压强度研究

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航空学报 2013年第7期34卷 1627-1635页

作者：魏景超矫桂琼闫照明刘风雷西北工业大学力学与土木建筑学院陕西西安710129 中国商飞上海飞机设计研究院上海201210 北京航空制造工程研究所北京100024

由于连接技术是复合材料连接结构设计中的关键环节,所以本文通过试验研究了干涉配合对复合材料单钉双剪连接件挤压强度的影响作用,并建立了能预测复合材料连接件挤压强度的三维有限元数值模型。该模型考虑了钉孔接触、渐进损伤以及大变... 详细信息

由于连接技术是复合材料连接结构设计中的关键环节,所以本文通过试验研究了干涉配合对复合材料单钉双剪连接件挤压强度的影响作用,并建立了能预测复合材料连接件挤压强度的三维有限元数值模型。该模型考虑了钉孔接触、渐进损伤以及大变形理论,并采用了Hashin失效判据以及Tan材料性能退化准则,研究了不同干涉量(0%,0.5%,3%)配合方式对连接强度和刚度的影响作用。结果表明适量的干涉能提高连接挤压强度,而3%的过量干涉配合降低了连接挤压强度,却有较高的挤压弦向刚度,与试验结果相比,吻合较好。

关键词：复合材料单面螺纹抽钉干涉配合紧固连接件渐进损伤

降温往复镦粗-挤压变形对Mg-Gd-Y-Zn-Zr合金晶粒细化及织构变化的研究（英文）

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稀有金属材料与工程 2018年第5期47卷 1422-1428页

作者：杜玥张治民张冠世闫钊鸣于建民中北大学山西太原030051

在480℃降温至370℃条件下,采用循环镦-挤工艺对均匀化后的Mg-Gd-Y-Zn-Zr合金进行变形,对循环镦-挤变形过程中的合金微观组织和织构变化进行研究。结果表明,随着循环镦-挤变形道次的增加,晶粒尺寸逐渐减小。在变形6道次后,累积应变达到8... 详细信息

在480℃降温至370℃条件下,采用循环镦-挤工艺对均匀化后的Mg-Gd-Y-Zn-Zr合金进行变形,对循环镦-挤变形过程中的合金微观组织和织构变化进行研究。结果表明,随着循环镦-挤变形道次的增加,晶粒尺寸逐渐减小。在变形6道次后,累积应变达到8.4,得到了平均晶粒尺寸为3.4μm的细小均匀的微观组织。晶粒细化是由非连续动态再结晶和连续动态再结晶复杂共同作用引起的。另外,变形过程中,原始粗大晶粒内的片层状长程有序相(LPSO)发生扭折变形产生扭折带,并在扭折带上发生动态再结晶,分割原始粗晶,起到晶粒细化作用。结果还表明,1道次镦-挤变形后,合金产生强的基面织构,随着变形道次的增加,织构强度有所减弱。织构弱化的原因是动态再结晶和加载力在轴向和径向交替变化共同作用。

关键词： Mg-Gd-Y-Zn-Zr合金往复镦-挤晶粒细化织构

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铆钉拉脱力估算和试验研究

科技创新导报 2013年第14期10卷 7-8页

作者：闫照明中国商飞上海飞机设计研究院强度设计研究部上海201210

该文通过试验研究了埋头铆钉和突头铆钉的拉脱破坏强度及拉脱破坏模式,给出了典型的铆钉拉脱破坏载荷,可供飞机设计使用。

关键词：铆钉拉脱力试验研究

热处理对GWZK94合金微观组织与力学性能的影响

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稀有金属材料与工程 2020年第5期49卷 1503-1511页

作者：朱家萱闫钊鸣张治民张冠世潘玉田张龙中北大学机电工程学院山西太原030051 湖北江山重工有限责任公司湖北襄阳441057 中北大学山西太原030051

为了改善铸态GWZK94合金微观组织的不均匀性,使用电阻加热炉在温度505~520℃范围内保温8~20 h进行热处理实验。采用光学显微镜(OM),差示扫描量热仪(DSC),X射线衍射仪(XRD),扫描电子显微镜(SEM),能谱仪(EDS),电子背散射衍射技术(EBSD),... 详细信息

为了改善铸态GWZK94合金微观组织的不均匀性,使用电阻加热炉在温度505~520℃范围内保温8~20 h进行热处理实验。采用光学显微镜(OM),差示扫描量热仪(DSC),X射线衍射仪(XRD),扫描电子显微镜(SEM),能谱仪(EDS),电子背散射衍射技术(EBSD),万能试验机和维氏硬度计进行微观组织演变及力学性能分析。结果表明,铸态合金组织主要包括树枝状α-Mg基体,含亚稳态层错(SFs)的片层结构,共晶相Mg24(Gd,Y,Zn)5,块状长周期有序堆垛结构(LPSO,Mg12(Gd,Y)Zn)和少量的富稀土相。在均匀化处理过程中,片层结构和共晶相Mg24(Gd,Y,Zn)5逐渐溶于基体中,同时块状LPSO相体积分数逐渐减小并伴随有片层状LPSO相向晶粒内部生长,颗粒状相在晶界附近析出。加热温度为520℃时出现复熔三角晶界,说明此时发生了合金的过烧现象。经过均匀化处理后,合金的极限抗拉强度(UTS)和拉伸屈服强度(TYS)表现出了与组织演变规律相同的变化趋势,同时得到了较为均匀的硬度分布。最佳的均匀化制度为515℃/16 h。

关键词： GWZK94合金均匀化 LPSO 组织力学性能

β-甘露聚糖酶的结构、特性及其在畜禽生产中的应用

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动物营养学报 2021年第5期33卷 2535-2543页

作者：殷运菊闫昭明陈清华刘明峰湖南农业大学动物科学技术学院长沙410128 山东隆科特酶制剂有限公司沂水276400

甘露聚糖广泛存在于豆粕、棕榈仁粕和芝麻粕等植物性饲料中,畜禽采食后会增加消化道内食糜黏度,降低饲粮的营养物质消化利用率。β-甘露聚糖酶可水解甘露聚糖生成甘露糖单元,其在畜禽饲粮中添加可补充内源消化酶的不足,消除和降解饲料... 详细信息

甘露聚糖广泛存在于豆粕、棕榈仁粕和芝麻粕等植物性饲料中,畜禽采食后会增加消化道内食糜黏度,降低饲粮的营养物质消化利用率。β-甘露聚糖酶可水解甘露聚糖生成甘露糖单元,其在畜禽饲粮中添加可补充内源消化酶的不足,消除和降解饲料原料中的抗营养因子,从而提高饲料转化利用效率,改善动物生长性能。本文就β-甘露聚糖酶的酶学特性及其在畜禽生产中的应用进行综述,为β-甘露聚糖酶在畜禽饲料中的应用推广提供参考和理论依据。

关键词：甘露聚糖 β-甘露聚糖酶酶学特性畜禽生产