Effect of Cold Deformation Ratio and Reheating Temperatures on Microstructure of AA7075 Alloy Produced by SIMA Process

Öz

The effect of cold deformation ratio and reheating temperatures was investigated on the microstructure of AA7075 alloy produced by the strain-induced melt activation (SIMA) process. For this aim, cold deformed billets with different ratios (10%, 20%, and 30%) were quenched in water from 600 °C, 606 °C, and 611 °C, and microstructural evolution was studied. It was observed that grain size reduced, shape factor increased with the increasing cold deformation ratio, and grain size and shape factor increased with the rising reheating temperatures. It was determined that a minimum of 20% cold deformation is required to produce a thixotropic structure with a homogeneous globular microstructure. It was also observed that the change in shape factor was insignificant with increasing temperature.

Anahtar Kelimeler

• AA7075 alloy
• SIMA process
• Thixotropic structure
• Reheating temperature
• Cold deformation ratio
• Semi-solid Processing.

Soğuk Deformasyon Oranı ve Yeniden Isıtma Sıcaklıklarının SIMA İşlemi ile Üretilen AA7075 Alaşımının Mikroyapısı Üzerine Etkisi

Öz

Gerinimin neden olduğu ergiyik/sıvı aktivasyonu (SIMA) işlemi ile üretilen AA7075 alaşımının mikroyapısı üzerine soğuk deformasyon oranı ve yeniden ısıtma sıcaklıklarının etkisi araştırılmıştır. Bu amaçla, farklı oranlarda (%10, %20 ve %30) soğuk deforme edilen kütükler 600 °C, 606 °C ve 611 °C sıcaklıktan hızla suda soğutularak mikroyapı değişimleri incelendi. Artan soğuk deformasyon oranı ile tane büyüklüğünün azaldığı ve şekil faktörünün arttığı, artan yeniden ısıtma sıcaklıklarında da tane büyüklüğü ve şekil faktörünün arttığı gözlenmiştir. Homojen küresel yapıya sahip bir tiksotropik yapı oluşturmak için minimum %20 soğuk deformasyonun gerekli olduğu belirlenmiştir. Artan yeniden ısıtma sıcaklığıyla şekil faktörünün değişiminin anlamlı olmadığı belirlenmiştir.

Anahtar Kelimeler

• AA7075 alaşımı
• SIMA işlemi
• Tiksotropik yapı
• Yeniden ısıtma sıcaklığı
• Soğuk deformasyon oranı
• Yarı katı işlem.
• AA7075 alloy
• SIMA process
• Thixotropic structure
• Reheating temperature
• Cold deformation ratio
• Semi-solid Processing.

Kaynakça

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