Effect of Temperature on Surface Cracking Defects in AA7075 Hot Extrusion

Tatsuya Funazuka*, Kuniaki Dohda, Norio Takatsuji, Kaito Takano, Ngernbamrung Sukunthakan

*Corresponding author for this work

Research output: Chapter in Book/Report/Conference proceedingConference contribution


Aluminum alloys in the 7xxx series are high-strength alloys that are used in a wide variety of products in the transportation equipment and aerospace fields to reduce weight. In particular, the A7075 alloy has the highest strength and is expected to find further applications in a wide range of fields such as aircraft parts and sporting goods. However, low productivity is a problem due to its high deformation resistance, tendency to produce surface defects called tearing on the product surface, and short tool life. Tearing tends to occur under high temperature and high speed conditions, and is thought to be caused by local melting of Zn, an additive element, due to heat generation in processing. In this study, to improve the productivity of A7075 alloy, the profile was cooled during extrusion to prevent recrystallization of extrudate surface grains due to processing heat and to prevent processing heat during forming. In order to investigate the cooling effect, hot extrusion simulation was conducted. The cooling effect successfully suppressed the occurrence of tearing. These results indicate that cooling the extrudate during forming reduces the effect of heat generation during forming and prevents recrystallization of the extrudate surface grains and local melting of Zn.

Original languageEnglish (US)
Title of host publicationAchievements and Trends in Material Forming- Peer-reviewed extended papers selected from the 25th International Conference on Material Forming, ESAFORM 2022
EditorsGabriela Vincze, Frédéric Barlat
PublisherTrans Tech Publications Ltd
Number of pages7
ISBN (Print)9783035717594
StatePublished - 2022
Event25th International Conference on Material Forming, ESAFORM 2022 - Braga, Portugal
Duration: Apr 27 2022Apr 29 2022

Publication series

NameKey Engineering Materials
Volume926 KEM
ISSN (Print)1013-9826
ISSN (Electronic)1662-9795


Conference25th International Conference on Material Forming, ESAFORM 2022


  • 7075 aluminum alloy
  • cooling
  • hot extrusion
  • tearing

ASJC Scopus subject areas

  • Materials Science(all)
  • Mechanics of Materials
  • Mechanical Engineering


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