Z. K. Yao
,
H. Z. Cuo
,
M. Wang
,
F. Lan and P. F. Feng (Northwestern Polytechnical University
,
Xi' an 710072
,
China)
金属学报(英文版)
Isothermal flashless die forging process of Ti - alloy structural air - frame part with varying thickness rib has been modelled in this paper.The results of present study show that a upside - down trapezoid rib would be formed and buckling would occure as blank is reduced,if the thickness of billet is maller than or equal to the thickness of rib. During modelling process of structural air frame part with E type cross - section rib, the saddle or lap would be formed finally at the middle of transverse rib between ribs with increase in deformation.If metal is allowed to flow out at confluence of longitudinal and transverse rib, the lop defect would be eliminated,, but a pipe cavity is obvious on corresponding loca- tion of blank. of defect formation depends on distance of metal flow ,friction,temperature homoge- neity of the blank and complexity of the part.
关键词:
Ti alloy
,
null
,
null
Journal of Materials Research
The morphology of the dark and bright regions observed by transmission electron microscopy for the Zr(64.13)Cu(15.75)Ni(10.12)Al(10) bulk metallic glass strongly depends on the ion beam parameters used for ion milling. This indicates that the ion beam could introduce surface fluctuation to metallic glasses during ion milling.
关键词:
room-temperature
郑建邦
,
丁浩
,
郭益平
,
刘林
,
柳伟
,
李行健
金属学报
选用K4169Fe—Ni基高温合金，研究了向熔体中加入NixAlyTiz金属间化合物对合金冷凝后的晶粒尺寸、枝晶组织等凝固组织特征的影响结果表明，加入微量NixAlyTiz细化剂并控制合金液的均匀化处理过程可显著细化晶粒，将铸件整体晶粒细化至0、1—02mm；达到ASTM1—3级,同时、枝晶组织出现了由树枝晶向胞状晶的转变、并且NixAlyTiz细化剂的加入对合金的结晶特性及凝固组织无不良影响.
关键词:
Fe－Ni
,
grain refinement
,
nucleant
,
dendrite morphology
,
null
Powder Diffraction
K(2)Zn(3)(P(2)O(7))(2) was synthesized by solid state reaction and its crystal structure was determined by ab initio method from powder X-ray diffraction (XRD) data. The title compound was determined to be orthorhombic with space group P2(1)2(1)2(1), Z=4, and lattice parameters a=12.901(8) angstrom, b=10.102(6) angstrom, and c=9.958(1) angstrom. Values of lattice parameters from 303 to 573 K were measured by temperature-dependent XRD. Thermal expansion coefficients alpha(0), lattice parameters, and cell volume at 0 K were determined to be alpha(0)(a)=1.62327X 10(-4)/K, a(0)=12.855(4) angstrom, alpha(0)(b) = 1.17921 X 10(-4)/K, b(0)=10.070(8) angstrom, alpha(0)(c)=2.62364X 10(-4)/K, c(0)=9.880(4) angstrom, and alpha(0)(V) = 6.599 X 10(-2) /K, V(0) = 1278.967(0) angstrom(3). The specific heat equation as a function of temperature was determined to be C(p)=0.77115 +0.00231 T-1241.60027T(-2)- 1.4133 X 10(-6)T(2) (J/K g), for temperatures from 198 to 710 K. The melting point estimated from the mu-DTA heating curve is 795 degrees C. (C) 2008 International Centre for Diffraction Data. [DOI: 10.1154/1.2992517]
关键词:
K(2)Zn(3)(P(2)O(7))(2);structure determination;thermal expansion;coefficient;specific heat;powder-diffraction;refinement;zno
段沐枫
,
李宁
,
郑莹莹
,
肖军
,
李勇
宇航材料工艺
K-cor是应用Z-pin增强技术的一种新型高性能结构.本文以NHZP-1树脂为基体研究适合K-cor结构的半固化Z-pin拉挤工艺,得到固化度为51.25％的Z-pin为满足制备要求的最佳参数,并制作悬空装置采用两步法进行半固化Z-pin的植入和压弯,探索出压弯和后固化工艺.在此基础上,对试制的K-cor夹层结构进行平拉和剪切试验研究.结果发现,折弯长度是K-cor夹层结构的另一重要参数,较长的折弯长度会增加Z-pin与蒙皮的结合面积从而提高结构的拉伸性能.
关键词:
复合材料
,
半固化Z-pin
,
K-cor夹层结构
,
制备工艺
,
力学性能
王晓旭
,
陈利
材料工程
doi:10.3969/j.issn.1001-4381.2011.11.001
通过单根Z-pin从复合材料层合板中拔出的试验方法,测试了Z-pin的拔出强度,计算了Z-pin的临界埋入深度,并引入抗拉强度利用率概念来表征Z-pin的抗拉强度在拔出过程中的利用程度.结果表明,直径0.50mm和0.28mm的Z-pin临界埋入深度分别约为5.1mm和3.1mm.当Z-pin的埋入深度小于临界埋入深度时,Z-pin从层板中拔出；Z-pin拔出强度与埋入深度成正比,与Z-pin的直径成反比；当Z-pin的埋入深度大于临界埋入深度时,Z-pin发生断裂,Z-pin的抗拉强度利用率达到100％.最后提出了提高抗拉强度利用率的建议.
关键词:
Z-pin
,
拔出强度
,
复合材料
,
拔出试验
,
抗拉强度
刘韡
,
矫桂琼
,
张为民
材料科学与工程学报
提出手工预缝纫方法将3K丝束的T300碳纤维引入预成型体,采用CVI工艺在预成型体和缝线处同时渗透SiC基体,制备了Z-pin增强平纹编织C/SiC陶瓷基复合材料。通过三点弯曲试验测定了Ⅰ＋Ⅱ混合型应变能释放率,分析了材料的裂纹扩展行为和Z-pin增强机理。结果表明：随着裂纹扩展长度的增大,Ⅰ＋Ⅱ型裂纹扩展阻力不断增大,相同裂纹扩展长度,增加Z-pin植入密度可以提高粘结强度,增大止裂作用。Z-pin增强平纹编织C/SiC陶瓷基复合材料裂纹扩展的耗能途径主要是层间界面剥离、Z-pin弹性剪切和拉伸变形。
关键词:
陶瓷基复合材料
,
断裂韧性
,
应变能释放率
,
Z-pin
