Entity

Time filter

Source Type


Li H.,Ningbo Jintian Copper Group Co. | Dai J.,Ningbo Jintian Copper Group Co. | Dai J.,Central South University
Xiyou Jinshu/Chinese Journal of Rare Metals | Year: 2010

Cu-Ag-Cr alloy was prepared by intermediate frequency melting-swage foundry-hot rolling-solution-cold rolling-aging process. The effects of minim Cr and Ag on structure and properties of the solution-cold rolling-aging alloy were studied by using tensile test, hardness test and TEM analysis. The relation between the quantity of Cr and yield strength was established. The results showed that addition of trace amount Ag existed mainly in solid solution while that of Cr as singly Cr particles. The dimension of Cr particles ranged from several to decade nanometer and the Cr particles were coherent with matrix. The cold roll-aging alloy retained part of the dislocation substructure. Small dispersed particles could strongly pin dislocations, stabilize sub-structure from deformation, forbid dislocation motion and merger of sub-boundaries. Alloy remained high dislocation density, therefore reversion and crystallization were delayed. The main hardening mechanism was due to Ag solution, sub-structure strengthening and Cr particles precipitation. The addition of yield strength by theoretical calculation was close to by experimentation, difference between calculated and measured value of 5.5%. The amount of the Cr precipitates could be obtained by the approximate calculation. Source


He Y.-F.,Ningbo Academy of Product Quality Supervision & Inspection | Wang L.-X.,Ningbo Jintian Copper Group Co. | Chen J.-H.,Ningbo Jintian Copper Group Co. | Zhang X.-B.,Ningbo Academy of Product Quality Supervision & Inspection
Chinese Rare Earths | Year: 2014

An analysis method for simultaneous determination of Al, Cu, B, Ni, Co and Mn in Pr-Nd-Dy-Fe-B alloy by ICP-AES was developed. Selection of spectral lines was studied, and effects of matrix content changes, acidity, power and atomization pressure on determination were tested, and the accuracy and standard recoveries of analysis results for this method were determined. The results show that the method was rapid and accurate, the relative standard derivation (RSD) was less than 4%, the recoveries were 94.10% ~ 105.1%, and the analysis results were same to chemical analysis method. The method can meet the production needs for analysis. ©, 2014, Editorial Office of Chinese Rare Earths. All right reserved. Source


Dai J.Y.,Ningbo Jintian Copper Group Co. | Dai J.Y.,Central South University | Mu S.G.,Ningbo Jintian Copper Group Co. | Mu S.G.,Central South University | Wang Y.R.,Ningbo Jintian Copper Group Co.
Advanced Materials Research | Year: 2011

The hot deformation behavior of Cu-0.35Cr-0.15Zr (wt.%) alloy was investigated by hot compression tests using a Gleeble-1500D thermal simulator system. The tests were performed under the conditions of 700°C- 820°C temperature and 0.01-10s-1 strain rate. The results show that the flow behavior of the studied alloy could be described by the hyperbolic sine constitutive equation, and an active energy of 597.53 kJ/mol was calculated. The processing maps were obtained and analyzed according to the dynamic materials model. The optimum processing parameters of hot deformation of this alloy in the range of this experiment can be attained by the maps. The hot deformation temperature was 800-820oC and the strain rate was 0.01-0.1s -1.The instability zones of flow behavior can also be recognized by the maps. © (2011) Trans Tech Publications. Source


Da J.-Y.,Ningbo Jintian Copper Group Co. | Da J.-Y.,Central South University | Mu S.-G.,Ningbo Jintian Copper Group Co. | Mu S.-G.,Central South University | And 3 more authors.
Advanced Materials Research | Year: 2011

The degassing and dedusting mechanism of La and Ce during non-vacuum melting process of Cu-Cr-Zr alloy were analyzed by thermodynamics. The gibbs free energy changes of reactions of La and Ce with some impurties such as O2, H2, S, P and Si, were calculated to discriminate the possibility of reaction during the melting process, respectively. in addition, the effect of La and Ce on microstructure and properties were studied. The results show that La and Ce can react with O2, H2, S, P and Si, which improves the effect of degassing and dedusting remarkably; the addition of La and Ce can eliminate pine-tree crystal, fine grain and clear grain bourdary. © (2011) Trans Tech Publications. Source


Li J.,Central South University | Li J.,Ningbo Jintian Copper Group Co. | Wang Y.,Ningbo Jintian Copper Group Co. | Dai J.,Ningbo Jintian Copper Group Co. | And 2 more authors.
Applied Mechanics and Materials | Year: 2012

The effects of different solid-solution temperature (500, 600, 700, 800, 900°C) and holding time (0.5, 1, 1.5, 2h) on properties and microstructure of Cu-Zn-Al-Ni alloy were investigated experimentally. The result shows that the hardness of the alloy presents lowest at 700°C and then increases gradually as a function of temperature. It is also revealed that hardness has no relation with the holding time. Phase transition occurs when the temperature is 900°C, as a result of which increases the hardness of the alloy. © (2012) Trans Tech Publications. Source

Discover hidden collaborations