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快速凝固Cu-Cr-Zr-Mg合金的时效析出与再结晶 总被引:47,自引:6,他引:41
对快速凝固Cu0.6Cr0.15Zr0.05Mg合金伴随时效析出的再结晶过程进行了观察和研究。发现该合金在形变后的时效过程中,析出相非常细小、弥散,阻碍了再结晶的进行,出现了原位再结晶与不连续再结晶同时发生的现象。在再结晶的形核和长大过程中,析出相在晶界前沿快速粗化或重新溶解,并在再结晶区域中重新析出,导致更加弥散的析出相分布。 相似文献
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EFFECT OF COLD WORKING ON THE AGING PROPERTIES OF Cu-Cr-Zr-Mg ALLOY BY ARTIFICIAL NEURAL NETWORK 总被引:1,自引:0,他引:1
J.H.Su H.J.Li Q.M.Dong P.Liu B.X.Kang B.H.Tian 《金属学报(英文版)》2004,17(5):741-746
A developmental research has been carried out to deal with the high performance of Cu-Cr-Zr-Mg lead frame alloy by artificial neural network (ANN). Using the cold working to assist in the aging hardening can improve the the hardness and electrical conductivity properties of Cu-Cr-Zr-Mg lead frame alloy. This paper studies the effect of different extent of cold working on the aging properties by a supervised ANN to model the non-linear relationship between processing parameters and the properties. The back-propagation (BP) training algorithm is improved by Levenberg-Marquardt algorithm. A basic repository on the domain knowledge of cold worked aging processes is established via sufficient data mining by the network. The predicted values of the ANN coincide well with the tested data.So an important foundation has been laid for prediction and optimum controlling the rolling and aging properties of Cu-Cr-Zr-Mg alloy. 相似文献
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J.H. Su P. Liu Q.M. Dong H.J. Li F.Z. Ren B.H. Tian 《Journal of Materials Engineering and Performance》2007,16(4):490-493
Recrystallization and precipitation behaviors after cold rolling and aging are investigated for Cu-0.7Cr-0.13Zr alloy. The
processed alloy was characterized using the measurement of Vickers hardness, scanning electron microscopy, and transmission
electron microscopy. The resultant complex microstructures are interpreted in terms of the interactions between precipitation
and recrystallization. Upon aging at 500 °C for 1 h, the 45% rolled alloy exhibits a retarded recrystallization process and
therefore an efficient hardening response, which are attributed to the pinning effect of fine dispersed precipitates on the
dislocation. When heavily deformed and aged at high temperature, the alloy shows an accelerated process of recrystallization,
and precipitates are found to coarsen. 相似文献
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Su Juan-hua Li He-jun Dong Qi-ming Liu Ping Kang Bu-xi 《Journal of Materials Engineering and Performance》2005,14(3):363-366
It is known that the strength of a metal can be successfully improved by rapid solidification. The hardness of the rapidly
solidified Cu-Cr-Sn-Zn alloy is much higher than that of the solution heat-treated and aged alloy. In this study, multiple-layer,
feed-forward, artificial neural network (ANN) modeling has been used to study the hardness and electrical conductivity behavior
of a rapidly solidified Cu-Cr-Sn-Zn alloy. The ANN model shows how the aging parameters influence the hardness and electrical
conductivity of a rapidly solidified Cu-Cr-Sn-Zn alloy. The ANN modeling also provides encouraging predictions for information
not included in the trained set samples, indicating that a backpropagation network is a very useful and accurate tool for
property analysis and prediction. 相似文献
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MANG Weishi WANG Guozhi ZHANG Yongchang HU Zhuangqi SHI Changxu Institute of Metal Research Academia Sinica Shenyang China Yongchang Associate Professor Institute of Metal Research Academia Sinica Shenyang China 《金属学报(英文版)》1990,3(4):236-242
A rapidly solidified microcrystalline Al-Li-Cu-Mg-Zr alloy and its superplasicity have beeninvestigated.An optimum tensile elongation of 585% was obtained at 540℃ and strain rate1.67×10~(-2)s~(-1).The superplastic Al-Li alloy is manufaetured using thermomechanical pro-cessing:solution,overaging,warm rolling and recrystallization.Microstructural changes inthermomechanical processing and cavitation occurred during superplastic deformation havebeen observed.The superplastic failure of alloy may be caused mainly by nucleation andgrowth of cavities as well as the linkage around grains. 相似文献
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Establishing the knowledge repository of rapidly solidified aging Cu-Cr-Zr alloy on the artificial neural-network 总被引:1,自引:0,他引:1
SUJuanhua DONGQiming LIUPing LIHejun KANGBuxi TIANBaohong 《稀有金属(英文版)》2004,23(2):171-175
The non-linear relationship between parameters of rapidly solidified aging processes and mechancal and electrical properties of Cu-Cr-Zr alloy is available by using a supervised artificial neural network (ANN). A knowledge repository of rapidly solidified aging processes is established via sufficient data learning by the network. The predicted values of the neural network are in accordance with the tested data. So an effective measure for foreseeing and controlling the properties of the processing is provided. 相似文献
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The structure evolution driven by recrystallization in the bulk undercooled Ni54.6Pd45.4 alloy was investigated by quenching the sample at different cooling stages. It is found that recrystallization of the solid beyond the critical undercooling for grain refinement starts at the end of rapid solidification, and develops during the slow solidification and the subsequent cooling process. At the initial stage of recrystallization, nuclei successively form in the sample, leading to a decrease in grain size. At the later stage, annexation of grains dominates the recrystallization, due to which the grain size increases. As undercooling prior to solidification increases, the deformation degree in the rapidly solidified dendrite net rises, and the recalescence temperature as well as the duration at high temperature decreases. Consequently, the grain size of the recrystallization structure decreases. 相似文献
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通过测量Cu-Cr-Zr-Co-Si冷轧合金在等温时效过程中导电率的动态变化,基于合金导电性能与析出相转化率间的近似线性关系,建立了不同冷变形量下合金时效析出过程的动力学Avrami方程及曲线,在此基础上分析了再结晶与时效析出的相互影响。结果表明:Cu-Cr-Zr-Co-Si合金形变时效过程中,随变形量和时效时间的增加,导电率及析出相转化率均增加,这是时效过程中再结晶与时效析出相互影响、共同作用的结果。随冷变形量增加,强化相析出进程明显加快,但时效析出没有明显阻止或延缓再结晶软化过程的发生,因此大冷变形+短时时效使合金获得更高的硬度峰值,但无法同时获得最优的导电性能。只有在时效析出提前于再结晶启动,且形成的第二相对再结晶存在明显阻碍的前提下,采用冷变形+时效工艺,时效强化型铜合金才能达到最佳效果。 相似文献
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采用快速凝固粉末冶金技术制备热挤压Mg_(80)Cu_(10)Y_(10)合金棒材,研究了快速凝固Mg_(80)Cu_(10)Y_(10)合金薄带及热挤压后合金的相结构,并对热处理工艺对合金棒材组织结构及力学性能的影响进行了分析.研究表明,采用单辊快速凝固法在辊速为1800 r/min下制备的Mg_(80)Cu_(10)Y_(10)合金薄带为完全非晶态;在热挤压过程中Mg_(80)Cu_(10)Y_(10)合金中有Mg_2Cu和Mg晶体相析出,其显微硬度比薄带有所提高,这与合金中细小Mg_2Cu颗粒的弥散析出有关;在450 ℃保温4 h后的热挤压Mg_(80)Cu_(10)Y_(10)合金中没有新相析出;随着热处理温度的升高或保温时间的延长,由于Mg_2Cu颗粒出现重溶及聚集长大现象,使得热挤压Mg_(80)Cu_(10)Y_(10)合金的显微硬度表现出逐渐下降的变化趋势. 相似文献
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《Acta Materialia》1999,47(4):1307-1323
Microstructural investigations on rapidly solidified Zr3Al based alloys (binary Zr3Al and ternary Zr3Al–3Nb and Zr3Al–10Nb) have revealed some unusual phase transformation sequences. The Zr5Al3 phase (D88 structure) has been found to occur in both the rapidly solidified ternary alloys unlike in the rapidly solidified stoichiometric Zr3Al alloy in which the Zr2Al phase (B82 structure) has been found to be present. The evolution of the D88 phase, which could be regarded as one of the ordered derivatives of the ω phase, could be described in terms of a superimposition of replacive and displacive ordering waves in the β phase. The orientation relationship between the β and the D88 phases has been established. The microstructural changes occurring in the rapidly solidified Zr3Al–Nb alloys during aging have been examined. It has been found that on aging the D88 phase gets transformed into the B82 phase which, on continued aging, transforms to other metastable and equilibrium phases, depending upon the aging temperature. The observed sequence of phase transformations involving different structurally related phases has been along the direction of progressively close packed structures. The symmetry changes associated with the sequence of ω related transformations have been summarized in the form of a symmetry tree. 相似文献
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Effect of trace rare earth element Er on Al-Zn-Mg alloy 总被引:4,自引:0,他引:4
1 Introduction Remarkable effects of rear-earth elements on aluminium alloys, such as eliminating impurities, purifying melt, refining as-cast structure, retarding recrystallization and refining precipitated phases, have been widely researched for a long… 相似文献
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快速凝固Cu—Cr合金时效析出的共格强化效应 总被引:43,自引:0,他引:43
采用单辊快速凝固的方法制备Cu-Cr合金微晶薄带,经适当的时效处理,可以在导电率不降低的前提下,显著提高合金的强度和硬度,强度和硬度的提高主要是由晶粒细化和共格弥散析出强化所造成,共格硬化效果与采用Gerold公式计算的结果非常接近,与常规固溶处理的Cu-Cr合金相比,峰值硬度提高了1.6倍,其中27%由细晶强化产生,73%则由时效析出的共格强化提供,固溶强化和空位强化对快速凝固Cu-Cr合金强度 相似文献
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The microstructures and mechanical properties of a new Mg-6%Zn-1%Mn(mass fraction) wrought magnesium alloy were studied,which could be extruded smoothly at 310-330℃with a complete dynamic recrystallization.After solution treatment one and two-step aging techniques were used.All as-aged microstructures contained two types of dispersed phases:β' phases and pureα-Mn particles.The two-step aging had a better strengthening effect than the traditional one-step aging,and the strength value achieved by the two-s... 相似文献
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Microstructure and thermal stability behavior of a rapidly solidified Al—Ti—Fe—Cr alloy 总被引:3,自引:0,他引:3
A rapidly solidified Al-2.5Ti-2.5Fe-2.5Cr(mass fraction in%) alloy was prepared by melt spinning.Asquenched and as-annealed microstructures were studied by X-ray diffractometry(XRD),transmission electron microseopy(TEM),high-resolution transmission electron microscopy(HREM) and energy dispersive spersive spectrum(EDS) analysis,The microhardness of the alloy at different annealing temperatures was measured.The results obtained indicate that the microhardness of the rapidly solidified Al-2.5Ti-2.5Fe-2.5Cr alloy does not vary with differnet annealing temperatures.The as-quenched microstructure of the alloy includes two kinds of dispersed primary phases:Al3Ti and Al13(Cr,Fe)2,After annealing at 400℃ for 10h,the stable phase Al13Fe4 appears in the microstructure. 相似文献