周清
,
伊藤吾朗
金属学报
处于介观尺度的材料的塑性变形行为不同于通常的宏观范围的材料，存在尺度效应。而且其变形也不同于微观尺度的材料[1]。研究处于介观尺度材料的塑性变形的重要意义在于，为微成形的基本成形规律的研究和工艺技术的发展铺平道路。通过在200C恒载荷的高温变形实验，研究厚度为10～350微米的铝合金箔的等温塑性变形行为。研究铝箔的厚度和晶粒大小对高温变形速率的影响规律。通过透射电子显微镜的观察可以发现在晶界旁存在亚晶界。用t/d参量能很好的描述塑变的尺度效应，随着t/d的减小，应变速率增大。t/d对应力指数也具有影响作用。得到一个经验的公式来描述应变速率和t/d的关系，用此公式能较好地模拟应力指数随t/d的变化。
关键词:
蠕变
,
aluminium alloy
,
thin foil
,
microforming
,
thickness
C. Y. Ban
,
J.Z. Cui
,
Q.X. Ba
金属学报(英文版)
The structures and macro-segregation of 2124 Al-alloy were studied when a pulsedmagnetic field (PMF) was applied during solidification. It is found through experi-ments that a remarkable change occurs in the solidification structures of 2124 Al-alloyunder pulsed magnetic field. The eutectic phase at grain boundaries change from thickcontinuous eutectic network to thin discontinuous one, and the distribution of soluteelements was also homogenized. The typical negative segregation phenomenon of Cu incommon solidification condition was restrained, and the segregation of Mg decreased.
关键词:
aluminium alloy
,
null
,
null
,
null
ZENG Xianghua
,
SHA Jiande
,
SU Ge Institute of Metal Research
,
Academia Sinica
,
Shenyang
,
ChinaYUAN Jigang LIU Fumei ZHONG Huiwen Southwest Aluminium Mill
,
China National Nonferrous Metals Industry Corporation
,
Chongqing
,
China SHA Jiande
,
Engineer
,
Institute of Metal Research
,
Academia Sinica
,
Shenyang
,
China
金属学报(英文版)
The end grain attack of LDIOCS aluminium alloy plates during chemical milling in hot aqueous solution of sodium hydroxide has been studied.The results show that the microsegregation of some components,i.e.Cu,Si etc.,is the main reason of the end grain at- tack,and it is affected by the conditions of heat treatment as well.The end grain attack significantly diminishes while some technical measures which are beneficial to the reduce of segregation were taken during melting and casting.
关键词:
aluminium alloy
,
null
,
null
,
null
ZHU Zuming Institute of Metal Reasearch
,
Academia Sinica
,
Shenyang
,
PRC.
材料科学技术（英文）
The longitudinal(L),long-transverse(T) and short-transverse(S)orientated samples of precipitation-strengthened 7075-T651 aluminum alloy were examined. The acoustic emission(AE)characteristics measured during tensile deformation in the alloy were related to prior aging treatment and orienta- tions of samples. A rms AE peak occurred in all the samples at plastic strain greater than one percent. The heights of peaks have been measured as a function of prior heat treatment.The shift of the peak location was dependent on heat treat- ment in samples with L- and T-orientation. The pre-yield,burst-type emission(PYBE)were observed in S-orientated samples.The behaviours of PYBE were as a function of prior ageing treat- ment too. The stress and plastic strains at which the AE peak stress were generated were consistent with the peaks arising from the fracture and debonding of inclusions.Waveform frequency analysis of AE signals and fractographic observa- tions using SEM as well as data of microhardness and charpy test were also consistent with be- haviours of AE,that is,high stress required for the rms peak or the initiation of the PYBE, was higher for the heat treatment,at which the interface between inclusion and matrix was weaker.
关键词:
acoustic emission
,
null
,
null
,
null
S. X. LÜ
,
J. C. Yan
,
W. G. Li
,
S. Q. Yang
金属学报(英文版)
The thermal model of FSW based on the thermal elastic-plastic finite element method, and the transient temperature distribution of FS welded joints of 2024-T4 Al was simulated by using this model, which provides useful information for the investigation of FSW process. Simulation results show that the temperature distribution of the weld gradually decreases toward periphery in a radiate format, whose center is the probe, and the highest temperature in the weld can reach about 400℃. The initial terminal of the weld is a zone, in which the temperature gradient is great, and defects of the welding are easily produced in this zone. Temperature change at the end of the weld joint is as layer variation, the local serious defects are not easy to produce in this zone.
关键词:
friction stir welding
,
null
,
null
A. GUNGOR
,
H. DEMIRTAS
中国有色金属学报(英文版)
doi:10.1016/S1003-6326(16)64199-7
研究掺杂了0.1%Fe、0.2%Fe 和0.5%Fe(摩尔分数)的电弧熔炼 NiAl?28Cr?6Mo 共晶合金在室温和高温条件的显微组织和力学性能。合金的均匀化热处理在 Ar 气气氛中于1300°C 条件下进行。采用金相分析技术、硬度测试、X 射线衍射分析技术及压缩试验对合金样品进行表征。结果表明，铸态和均匀态合金均呈较细的晶内共晶结构和较粗的晶间共晶结构。Fe 含量的增加导致共晶层粗化及共晶数量减少。在室温条件下所有实验合金均具有很高的压缩应力和应变。Fe 的添加对室温条件下合金的强度和延展性的影响较小；然而，Fe 的添加使合金的高温强度增加。高温条件下，X 射线衍射峰向低 Bragg 角方向移动，这表明 Fe 的添加使合金的晶格常数增大。
关键词:
铝合金
,
微合金化
,
固-液硬化
,
脆性
,
延展性
,
显微组织
,
力学性能
吴珺仪
,
李忠盛
,
吴护林
,
李立
表面技术
采用复合化学镀方法在铝合金微弧氧化陶瓷膜表面制备了Ni-P-SiC复合镀层,研究了镀液中SiC浓度对复合镀层物相、显微组织、沉积速率的影响,并测试了复合涂层(陶瓷J/复合镀层)的结合力.结果表明:Ni-P-SiC复合镀层为非晶态结构,与陶瓷膜的界面清晰,完全封闭了微弧氧化陶瓷膜表面的微孔;随着镀液中SiC含量的增加,复合镀层沉积速率降低,SiC共析量则是先快速增大,当含量达到16 g/L后就基本保持不变.
关键词:
复合化学镀
,
Ni-P-SiC镀层
,
铝合金
,
微弧氧化
