The Effects of Zn, Cu and Mg Elements on Ageing, Microstructure and Hardness in Al Alloys Produced by P/M Method

Abstract

In this study, two different compositions contain pure Al, Zn, Cu and Mg were produced by powder metallurgy. The powders were pressed under 800 MPa and sintered in purity argon
atmosphere at 600ºC after pressing process. Solution heat treatment were applied to sintered samples at 480ºC and then rapid quenching was performed. For quenched samples; Ageing process was carried out at 120ºC for 3h periods totally 12 hours. As a result, the ageing process leads to increased hardness due to the homogeneously dispersed secondary precipitates that form internally in the microstructure. 

Keywords

• Powder Metallurgy
• Ageing
• Solution Treating
• Al-Zn-Cu-Mg Alloy

T/M Yöntemi ile Üretilen Al Alaşımlarında Zn, Cu ve Mg Elementlerinin, Yaşlanma, Mikroyapı ve Sertliğe Etkileri

Öz

Bu çalışmada, saf haldeki Al, Zn, Cu ve Mg tozlarından mekanik öğütme ile iki farklı kompozisyonda malzeme üretilmiştir. Daha sonra tozlar 800 MPa basınç altında preslenmiş ve presleme sonrası 600ºC’de atmosfer kontrollü fırında (yüksek saflıktaki argon) sinterleme işlemine tabi tutulmuştur. Sinterlenen numunelere 480ºC’de çözündürme işlemi uygulandıktan sonra, hızlı su verme işlemi gerçekleştirilmiştir. Su verilen numunelere ise; 120 ºC yaşlandırma sıcaklığında, 3’er saat arayla, toplamda 12 saat yaşlandırma işlemi uygulanmıştır. Numunelerde yaşlanma ve sinterlemenin etkilerini incelemek için FESEM, Optik Mikroskop, Element Dağılım Spektrometresi, Haritalama (MAP), sertlikteki etkileri incelemek için mikrosertlik ölçümleri gerçekleştirilmiştir. İncelemeler sonucunda yaşlanma sonrası sertlikte artış meydana gelmiş ve sertlikteki bu artışın mikroyapıda içten oluşumlu şekilde meydana gelen çökeltilerin sayesinde olduğu gözlemlenmiştir.

Anahtar Kelimeler

• Toz metalürjisi
• Yaşlandırma
• Çözeltiye Alma
• Al 7075

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