Influence of the pre-homogenization treatment on the microstructure evolution and the mechanical properties of Al–Cu alloys processed by ECAP

Abstract As an indispensable pre-treatment for aging, homogenization treatment has a significant effect on precipitation behavior of the Mg-RE alloys. Herein, the influence of homogenization temperature on the microstructure evolution and mechanical performance of a novel Mg-2.0Nd-2.0Sm-0.4Zn-0.4Zr (wt.%) alloy has been studied systematically. The results indicated that the as-cast alloy was mainly composed of α-Mg matrix, β-Mg12(Nd,Sm,Zn) phase and Zr-containing particles. Upon increasing the homogenization temperature from 500 oC to 525 oC for 8 h, the average grain size of as-homogenized alloy increased from 76 μm to 156 μm, and the content of β phase decreased gradually. It was worth noting that the homogenization temperature exceeded 515 oC, the β phase at the grain boundaries was completely dissolved. After aging at 200 oC for 18 h, numerous of plate-like β' phases were observed in α-Mg matrix. The rise in homogenization temperature was conducive to nucleation and growth of the β' phase. However, excessive homogenization temperature significantly coarsened grain size. The aged alloy under homogenization treatment at 515 oC for 8 h achieved optimal mechanical properties. The values of ultimate tensile strength, yield strength and elongation were 261 MPa, 154 MPa and 5.8 %, respectively. The fracture mode of the aged alloy mainly exhibited a typical transgranular cleavage fracture.

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Influence of Fe-rich particles on microstructure evolution, texture and mechanical properties of Al–Mg–Si–Cu alloys

Metallurgical Research & Technology ◽

10.1051/metal/2020053 ◽

2020 ◽

Vol 117 (5) ◽

pp. 508

Author(s):

Libo Yu ◽

Lin Chen ◽

Hebin Wang ◽

Xiaofeng Wang ◽

Wenfei Peng ◽

...

Keyword(s):

Mechanical Properties ◽

Microstructure Evolution ◽

Fine Particle ◽

Particle Distribution ◽

Solution Treatment ◽

Alloy Sheet ◽

Grain Structure ◽

Cu Alloys ◽

Solution Treated ◽

Equiaxed Grain

The influence of Fe-rich particles on the microstructure evolution, texture and mechanical properties of Al–Mg–Si–Cu alloys was investigated by means of microstructure, texture and mechanical property analysis in the present study. The results show that Fe-rich particles have a significant influence on the microstructure evolution, texture, and final mechanical properties. Although both alloy sheets with different numbers of Fe-rich particles possess the similar microstructure including grain structure and fine particle distribution before solution treatment, the alloy sheet with a large number of Fe-rich particles possesses finer equiaxed grain structure in comparison with the alloy sheet with a medium number of Fe-rich particles after solution treatment. The solution treated alloy sheet with a medium number of Fe-rich particles is mainly comprised of CubeND {001}<310> orientation, while the solution treated alloy sheet with a large number of Fe-rich particles possesses weaker texture consisting of CubeND and Goss {110}<001> orientations. Fe-rich particles are beneficial to improve yield strength, ultimate tensile strength and r value, whereas reduce n and Δr values. Finally, the effect of Fe-rich particles on recrystallization microstructure and texture was analyzed.

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