陈志国
,
郑子樵
,
王芝秀
,
李世晨
材料研究学报
通过时效硬化曲线的测量、室温拉伸实验以及时效组织的电镜观察,
研究了添加锂对低Cu/Mg比Al--Cu--Mg--Ag合金时效特性的影响. 结果表明,
在Al--4.0Mg--1.5Cu--0.4Ag合金中添加锂, 可以加速合金的时效进程,
但其时效硬化效果并不能简单地随着含锂量的增加而逐步加强,
只有当锂含量达到2.0\%(质量分数)时, 才表现出显著的时效硬化与强化效果.
含2.0\%Li的Al--4.0Mg--1.5Cu--0.4Ag合金中$Z$相、$\delta^{\prime}$以及
$\delta^{\prime}$/$\beta^{\prime}$复合粒子的弥散析出是产生显著时效硬化与强化的原因.
关键词:
金属材料
,
Al alloy
,
ageing
,
microstructure
,
lithium
毕敬
,
马宗义
,
吕毓雄
,
宁小光
,
高荫轩
金属学报
本文对粉末冶金法制备的SiC晶须增强2124Al和2024Al两种复合材料进行了拉伸试验和断口观察,TEM和HREM证实在SiC_w/2024Al界面处存在链状不连续分布的θ(Al_2Cu)沉淀相,这种沉淀相降低了复合材料的室温强化效果,并对其塑性产生不利的影响。
关键词:
复合材料
,
SiC
,
Al alloy
,
interface
马宗义
,
姚忠凯
金属学报
本文对SiC_w/6061Al复合材料的组织与性能进行了研究,结果表明,压铸法可以制备出高强度、高模量的各向同性复合材料,挤压使复合材料的强度由压铸态的582MPa提高到639MPa,并使材料变为各向异性,这可以由晶须的定向排列和基体的高密度位错得到解释。复合材料的抗高温性能要比基体高150℃,透射电镜观察还发现,层错是SiC晶须中常见的一种面缺陷。
关键词:
复合材料
,
SiC whisker
,
Al alloy
,
microstructure
B.H. Kim N.H. Kang W.T. Oh C.H. Kim J.H. Kim Y.S. Kim Y.H. Park
材料科学技术（英文）
For Al 6k21-T4 overlap weld joint, the shear-tensile strength by using the weaving laser was improved as compared to the case of linear laser. For the specimen of low strength, the porosity was distributed continuously along the intersection between the plates and fusion line. However, for the optimized welding condition, large oval-shaped porosities were located only in the advancing track of the concave part. Therefore, the continuity of cracks and porosities played a key role to determine the strength. And, the weaving width was also the important parameter to control the strength. Furthermore, the concave part had more significant hot and cold cracking in the weld and heat-affected zone (HAZ), respectively, than the convex part.
关键词:
Weaving laser
,
Weld microstructure
,
Void
,
Al alloy
B.H. Kim N.H. Kang W.T. Oh C.H. Kim J.H. Kim Y.S. Kim Y.H. Park
材料科学技术（英文）
For Al 6k21-T4 overlap weld joint, the shear-tensile strength by using the weaving laser was improved as compared to the case of linear laser. For the specimen of low strength, the porosity was distributed continuously along the intersection between the plates and fusion line. However, for the optimized welding condition, large oval-shaped porosities were located only in the advancing track of the concave part. Therefore, the continuity of cracks and porosities played a key role to determine the strength. And, the weaving width was also the important parameter to control the strength. Furthermore, the concave part had more significant hot and cold cracking in the weld and heat-affected zone (HAZ), respectively, than the convex part.
关键词:
Weaving laser
,
Weld microstructure
,
Void
,
Al alloy
黄岩
,
崔建忠
,
马龙翔
金属学报
本文根据概率理论和金属扩散焊接过程中焊接面上原子激活的特点,建立了接合面上原子成键反应的数学模型,从而给出了焊接工艺参数和材料参数对接合强度的影响规律,模型中采用了界面上原子反应激活中心是界面位错及其弹性应力场的假设。文中以7075Al合金扩散焊接实验为基础,对模型进行了定量计算,计算结果与实验结果基本一致。
关键词:
扩散焊接
,
atomic reaction
,
Al alloy
WANG Shuncai LI Chunzhi YAN Minggao Institute of Aeronautical Materials
,
Beijing
,
China BIAN Weimin Northeast Institute of Technology
,
Shenyang
,
China WANG Shuncai Graduated Student
,
Institute of Aeronautical Materials
,
Beijing 100095
,
China
金属学报(英文版)
X-ray microanalysis,convergent beam electron diffraction(CBD)and selected area electron diffraction(SAD)studies on the structures and compositions of the constituent phases in 2024 series Al alloys have been conducted.Partial substitution of alloying elements is found to occur in all the constituent phases,which cause small deviations from the stoichiometric com- positions reported in these ternary compounds.The dominant phase is α-Al_(12)(FeMn)_3Si which has a body center cubic crystal structure with the Im■ space group and a=1.25 nm.The next dominant phase is Cu_2FeAl_7 which has a primitive tetragonal crystal structure with the P4/mnc space group and a=0.6336 nm,c=1.487 nm.The minor phase is α'-Al_(12)Fe_3Si hav- ing α primitive cubic crystal structure with the Pm■ space group and α=1.27 nm.
关键词:
Al alloy
,
null
,
null
LI Huanxi CHEN Changqi Beijing University of Aeronautics and Astronautics
,
Beijing
,
China
金属学报(英文版)
Contributions of weak grain boundary,cracking path deflection and grain boundary delamination to fracture toughness anisotropy of high strength Al alloys were evaluated based upon approaches of fracture mechanics in conjunction with physical cracking mechanisms. The predicted results are close to those experimentally determined in the literature and in this work.The strong anisotropy of fracture toughness of high strength Al alloys is therefore attri- buted mainly to weak grain boundary cracking,cracking path deflection and grain boundary detamination.With the methods of this work,short-transverse fracture toughness values of some semi-products can he estimated from in-plane toughness values and corresponding frac- ture characteristics when it is difficult to be determined experimentally.
关键词:
Al alloy
,
null
,
null
