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Materials Science and Engineering of Powder Metallurgy >

2022 , Vol. 27 >Issue 2: 140 - 150

DOI: https://doi.org/10.19976/j.cnki.43-1448/TF.2021092

Engineering and Technology

Microstructure and mechanical properties of powder hot extruded 7075 aluminium alloy

  • JING Cuiru ,
  • ZHANG Jiantao ,
  • WEN Liping ,
  • XIAO Zhiyu
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  • National Engineering Research Center of Near-Net-Shape Forming for Metallic Materials, South China University of Technology, Guangzhou 510640, China

Received date: 2021-11-06

  Revised date: 2021-12-27

  Online published: 2021-12-20

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Abstract

7075 aluminum alloy bar was prepared by powder hot extrusion method. The microstructures of the alloy bar were examined by scanning electron microscopy (SEM), transmission electron microscopy (TEM), and X-ray diffraction (XRD). In addition, the tensile properties of the samples were also tested. The influences of the extrusion ratio on the microstructure and mechanical properties of the bar were investigated, and the strengthening mechanism was calculated in theory. The results show that a large number of second phase MgZn2 precipitates are desolventized and precipitated during hot extrusion at 500 ℃ with extrusion ratios of 9, 16, 25, and 36. With increasing extrusion ratio, the metallurgical bonding between the powder particles becames more sufficient, and the tensile strength and elongation of the alloy increase continuously. A high tensile strength of 492 MPa with an elongation of 27.6% is obtained at an extrusion ratio of 36. The fracture mode is a ductile-brittle-bonding fracture. The strengthening mechanism is the combined action of fine-grain strengthening, dislocation strengthening, second phase strengthening and solution strengthening.

Key words： powder hot extrusion; 7075 aluminium alloy; microstructure; mechanical property; strengthening mechanisms

Cite this article

JING Cuiru , ZHANG Jiantao , WEN Liping , XIAO Zhiyu . Microstructure and mechanical properties of powder hot extruded 7075 aluminium alloy[J]. Materials Science and Engineering of Powder Metallurgy, 2022 , 27(2) : 140 -150 . DOI: 10.19976/j.cnki.43-1448/TF.2021092

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