Paper Title:
Effect of Second Phases on Tensile Property in Artificial Ageing and RRA Process of Super-High Strength Aluminum Alloy
  Abstract

The evolution of second phases and its effect on tensile mechanical property in artificial ageing and RRA process of super-high strength aluminum alloy is investigated.The result of tensile test shows that the samples of Al-Zn-Mg-Cu-Ag alloy aged at lower temperature(100°C) not only have higher tensile strength up to 753Mpa but also relatively higher tensile elongation above 9% than normal temperature(120°C) in artificial ageing. The sample of Al-Zn-Mg-Cu alloy has the highest tension strength upto 788Mpa when aged at 100°C for 48 hours in single step of artificial ageing. Further more in RRA process samples of Al-Zn-Mg-Cu alloy preaged at 100°C for 24 hours retrogressed at 200°C for 7min and reaged at 100°Cfor 24 hours present the best tensile strength of 795Mpa than others. The tensile strength of Al-Zn-Mg-Cu alloy after RRA treated decreases with prolonging of retrogression time and reageing time starting from 7mins and 24 houres respectively. SEM observation shows that crack of the samples in tensile test is created at large particles in the fracture while there are more particles of undissolved phase in Al-Zn-Mg-Cu alloy containing Ag. TEM observation shows that the dominant strengthening particle corresponding to the peak strength of Al-Zn-Mg-Cu alloy containing Ag when aged at 120°C for 8 hours is η’ phase while dominant strengthening particle is G.P zone when aged at 100°C for 80 hours. However, η’ phase as the dominant strengthening particles corresponds to the peak strength of Al-Zn-Mg-Cu alloy without content of Ag when aged at 100°C for 48hours. TEM observation also shows that G.P zone as strengthening particle is dominant in the samples of Al-Zn-Mg-Cu alloy reaged at 100°C for 24 hours, and strengthening particles is coarsened when the sample is retrogressed at 200°C and reaged for a longer time. It is suggested that whether at the presence of coarse particles of undissolved phases or when G.P zone and η’ particle grow up in the retrogression ,sample needs deformable G.P zone instead of undeformable η’ in subsequent artificial ageing and reageing as dominant strengthening particle, in order to present a larger freedom spacing for dislocation to slip and let the sample not to behave too brittle to display high resistance to imposed plastic deformation or high tensile strength.

  Info
Periodical
Materials Science Forum (Volumes 546-549)
Edited by
Yafang Han et al.
Pages
855-862
DOI
10.4028/www.scientific.net/MSF.546-549.855
Citation
A. L. Ning, Z. Y. Liu, C. Feng, S. M. Zeng, "Effect of Second Phases on Tensile Property in Artificial Ageing and RRA Process of Super-High Strength Aluminum Alloy", Materials Science Forum, Vols. 546-549, pp. 855-862, 2007
Online since
May 2007
Export
Price
$32.00
Share

In order to see related information, you need to Login.

In order to see related information, you need to Login.

Authors: Jeong Min Kim, Bong Koo Park, Joong Hwan Jun, Ki Tae Kim, Woon Jae Jung
Abstract:Small amounts of minor alloying elements such as RE and Sr were added to Mg- 8wt%Al-5wt%Zn (AZ91D+4%Zn), and their effects on the...
374
Authors: E.P. Masuku, Gonasagren Govender, L. Ivanchev, Heinrich Möller
Abstract:Rheocasting of alloys A206 and A201 was investigated in this study. Conical bars with different silver contents were produced using CSIR...
151
Authors: Bao Hong Zhu, Bai Qing Xiong, Yon Gan Zhang, Udo Fritsching, Ji Shan Zhang, Feng Wang, Zhi Hui Li, Hong Wei Liu
Abstract:A high Zn content Al-Zn-Mg-Cu alloy was prepared by spray forming process and the precipitate behavior and microstructure of the extruded...
481
Authors: Xiao Ping Luo, Lan Ting Xia, Ming Gang Zhang
Abstract:The effect of Cd and Sb addition on the microstructural and mechanical properties of as-cast AZ31 alloys was investigated and compared. The...
197
Authors: Hong Wei Liu, Yon Gan Zhang, Jian Bo Zhang, Bao Hong Zhu, Feng Wang, Zhi Hui Li, Xi Wu Li, Bai Qing Xiong
Chapter 1: Materials Properties
Abstract:Microstructural characterization of Al-Cu-Mg-Ag alloy ageing at low and elevated temperature were investigated by differential scanning...
1225