L-F. Li
,
Z. Zhang
,
and Y Y Li(Cryogenic Laboratory Chinese Academy of Sciences
,
Beijing 100080
,
China)(Institute of Metal Research
,
Chinese Academy of Sciences
,
Shenyang 110015
,
China)
金属学报(英文版)
The microstructure of a fine-grained 16.5mol% CeO2 stabilized tetragonal zirconia polycrystal (Ce-TZP has been investigated by TEM and it is shown that the mi-crostructures of samples fractured at 298, 77 and 4.2 K change significantly. At 298K there is no stress-induced martensite but a few anti-phase boundaries (APBs) in tetragonal (t) parent phase. With a decrease in temperature, monoclinic (m) product or mariensite within retained t-phase appears. The morphologies are characterized as lenticular and block-like at 77 K and as lenticular and butterfly-like at 4.2 K. The relationship between microstructure and mechanical properties is also discassed in this paper.
关键词:
microstructure
,
null
,
null
B.W. Wang
,
H. Shen
金属学报(英文版)
Ni-Cr System solar selective thin solid films were prepared by d.c. magnetron reactivesputtering under the atmosphere of O2 and N2. Ni-Cr alloy was chosen as targetmaterial and copper sheets as substrate. Using SEM, Spectrophotometer and Talystepto analyze the relations between the selective characteristic and the structure, theformation and the thickness of the thin films. The aim is to obtain good solar selectivethin films with high absorptance and low emittance, which is applied to flat plate solarheat collectors.
关键词:
solar selective thin film
,
null
,
null
,
null
SUN Dongsheng LI Fengzhao ZHANG Gang Shandong Polytechnic University
,
Jinan
,
China Lecturer
,
Centre of Materials Testing and Analysis
,
Shandong Polytechnic University
,
Jinan 250014
,
China
金属学报(英文版)
Cryogenic strength,ductility and toughness of AI-Li alloy 8090 were found to be superior to those at ambient temperature,and up to optima at about 20 K.Different aging regimes may only influence on its cryogenic yield strength and elongation.
关键词:
Al-Li alloy
,
null
,
null
,
null
桂全红
,
马禄铭
,
蒋晓军
,
梁国军
,
李依依
材料研究学报
研究了两种不同Y 含量对8090Al-Li 合金拉伸性能及断裂行为的影响。实验表明:加入0.1wt-%Y 可在不降低强度的情况下提高合金的塑性,加入0.5wt-%Y 可在不降低塑性的情况下提高合金的强度。在峰值时效条件下,不加Y 的合金断裂为穿晶韧窝型和沿晶塑性混合方式,并伴有沿晶二次裂纹,加0.1%Y 不改变合金断裂模式,但使沿晶成分减少;加0.5%Y 合金则发生快速剪切断裂。本文从晶粒结构角度对断裂行为提出了解释。
关键词:
A—Li 合金
,
rare earth element Y
,
tensile properties
,
intergranular fracture
,
transgranular fracture
刘成
,
杨毅
,
韩正玉
,
武晓雅
,
翁景霞
,
林璐
中国稀土学报
doi:10.11785/S1000-4343.20130408
采用溶胶-凝胶法制备Li+掺杂改性的Y2SiO5:Pr3+上转换发光材料,考察了Li+掺杂对样品晶型及发光性能的影响.采用XRD,DSC-TGA,FS对所制备的材料进行表征,结果表明Li+掺入浓度在7％～ 8％(摩尔分数)之间会引起Y2SiO5晶体类型由X型转变为X2型,且Li+掺入后样品转晶型温度由950℃降至800℃;样品经800℃煅烧处理后以X1型Y2SiO5为主相,850℃煅烧处理后以X2型Y2SiO5为主相;Li+掺入同时会提高Y2SiO5:Pr3+材料的上转换发光强度,Li+最佳掺杂浓度为10％,对于双掺杂pr3+,Li+:Y2SiO5体系中pr3+最佳掺杂浓度为1.2％.
关键词:
溶胶-凝胶法
,
上转换
,
晶相转变
,
锂掺杂
,
稀土
沙桂英
,
刘翠云
,
刘腾
,
孙晓光
,
李根
材料工程
doi:10.3969/j.issn.1001-4381.2010.07.014
利用Hopkinson压杆技术对Mg-3.5%Li及Mg-3.5%Li-0.77%Y合金在不同应变率下进行了冲击压缩实验,分析了两种合金的动态应力-应变行为及其应变率效应.结果表明,随应变率提高,Mg-3.5%Li合金的应力-应变行为表现出应变率强化效应与应变率弱化效应的双重特性.添加稀土元素Y后,合金有所强化,但其应力-应变行为仍具有应变率弱化效应,随应变率提高产生的微裂纹引起的内部损伤是导致合金应变率弱化效应的主要原因.
关键词:
Mg-Li合金
,
Mg-Li-Y合金
,
应变率
,
微裂纹
冯剑
,
黄金亮
,
贾玉鑫
兵器材料科学与工程
为改善铸态Mg-12Li-3Gd-3Y-0.6Zr合金的力学特性，对铸锭进行均匀退火处理。采用金相显微镜、SEM、XRD、显微硬度测试和拉伸力学特性测试，观察和研究了试验合金的微观组织和力学特性。结果表明：最佳的均匀化退火工艺为500℃×8 h，均匀化退火后合金的抗拉强度由铸态的114 MPa提高到133 MPa。第二相形态及分布的改变是Mg-12Li-3Gd-3Y-0.6Zr合金力学特性改变的主要原因。
关键词:
镁锂合金
,
均匀化
,
微观组织
,
力学特性
彭晓东
,
李俊辰
,
李文娟
,
杨艳
,
魏群义
稀有金属材料与工程
采用光学显微镜、SEM扫描电镜、XRD以及力学性能和电化学测试等手段,研究了不同Y含量对Mg-9Li-3Al合金组织、力学性能和腐蚀性能的影响.结果表明:随着Y的添加,α相的形貌逐渐发生变化,其体积分数也逐渐减少,并形成新的Al2Y相,Al2Y主要分布在β相和α相内部.当Y的添加量为1.6％(质量分数)时,材料的抗拉强度达到最大190.2 MPa;当Y含量为2.0％时,材料的最大延伸率为19.3％.在Y含量低于1.2％时,材料的抗腐蚀性能随Y含量的增加而减小,超过1.2％后,随着Y含量的增加而增加.
关键词:
镁合金
,
组织
,
力学性能
,
抗腐蚀性能
稀土学报(英文版)
Er(3+) and Li(+) codoped Y(3)Al(5)O(12) (YAG) powders were prepared for a systematic investigation of their upconversion emissions. X-ray diffraction (XRD), upconversion emission spectra, pump power dependence, FT-IR spectra and decay time were studied to characterize the samples. With Li+ doping, the upconversion emission intensity of Er(3+) doped YAG powders was obviously enhanced, accompanied with an increase in the ratio of green to red intensity. The enhancement of emission intensity could be attributed to two mechanisms: one was the distortion of local crystal field around Er(3+), and the other was the decrease in the amount of CO(3)(2-) and OH(-) groups. Our results revealed that the latter was the dominant mechanism of the upconversion intensity enhancement in the YAG:Er(3+)/Li(+) powders.
关键词:
luminescence;optical materials and properties;sol-gel preparation;nanomaterials;rare earths;nanocrystals;nanophosphors;li+
