The Effect of Mechanical Alloying Time on the Hardness and Electrical Conductivity Properties of Cu-Cr Alloys Produced by Hot Pressing Method

Öz

This study concentrated on alloying 0.5% chromium reinforced copper particles by weight by mechanical alloying method according to different alloying times and intensifying the produced powders by hot press method. 10:1 ball:powder ratio and 400 rpm rotation speed were selected as mechanical alloying parameters and the times were determined as 0, 0.5, 1, 2 and 4 hours as variable. Hot pressing parameters were used as constant in all experiments and were determined as 500 ⁰C and 600 MPa. As a result of the experiments, it was determined that the powders with initially spherical and irregular morphology had a flake-like morphology after 0.5 hours of mechanical alloying. In addition, as a result of the experiments, the highest specific surface area was obtained after 1 hour of mechanical alloying and was measured as 0.0667 m2/g. The lowest and highest hardness values of the compact samples produced within the scope of this study belong to the samples that were not mechanically alloyed and subjected to 1 hour mechanical alloying, respectively, and were measured as 71.97 HB and 99.12 HB. The highest electrical conductivity value belongs to the sample subjected to mechanical alloying process for 4 hours and it was measured as 91.27% IACS. In this study, the effects of time, which is one of the mechanical alloying process parameters, on the morphology and size of the particles, the microstructure and physical and mechanical properties of the compact material were determined.

Anahtar Kelimeler

• Copper
• Chromium
• Mechanical Alloying
• Hot-Pressing
• Powder Metallurgy

Sıcak Presleme Yöntemi ile Üretilen Cu-Cr Alaşımlarının Sertlik ve Elektriksel İletkenlik Özellikleri Üzerine Mekanik Alaşımlama Süresinin Etkisi

Öz

Yapılan bu çalışmada ağırlıkça %0,5 krom takviyeli bakır partiküllerin mekanik alaşımlama yöntemi ile farklı alaşımlama süreleri kullanılarak alaşımlandırılması ve üretilen tozların sıcak pres yöntemiyle yoğunlaştırılması çalışmaları yer almaktadır. Mekanik alaşımlama parametreleri olarak 10:1 bilye:toz oranı, 400 dev/dk dönüş hızı seçilmiştir süreler ise değişken olarak 0, 0,5, 1, 2 ve 4 saat olacak şekilde belirlenmiştir. Sıcak presleme parametreleri tüm deneylerde sabit olarak kullanılmıştır ve 500 ⁰C ve 600 MPa olarak belirlenmiştir. Yapılan deneyler neticesinde başlangıçta küresel ve düzensiz morfolojiye sahip tozların 0,5 saat mekanik alaşımlama işlemi sonrasında pulsu benzeri morfolojiye sahip olduğu belirlenmiştir. Ayrıca yapılan deneyler sonucunda en yüksek spesifik yüzey alanı 1 saat mekanik alaşımlama işlemi neticesinde elde edilmiştir ve 0,0667 m2/g olarak ölçülmüştür. Bu çalışma kapsamında üretilen kompakt numunelerin en düşük ve en yüksek sertlik değerleri sırasıyla mekanik alaşımlama işlemi uygulanmamış ve 1 saat mekanik alaşımlama işlemine tabii tutulmuş numunelere aittir ve 71,97 HB ve 99,12 HB olarak ölçülmüştür. En yüksek elektriksel iletkenlik değeri de 4 saat mekanik alaşımlama işlemine tabii tutulmuş numuneye aittir ve 91,27 %IACS olarak ölçülmüştür. Yapılan bu çalışma ile mekanik alaşımlama işlem parametrelerinden biri olan sürenin parçacıkların morfolojisi ve boyutu ile kompakt malzemenin mikroyapısı ve fiziksel ve mekanik özellikleri üzerine etkileri belirlenmiştir.

Anahtar Kelimeler

• Bakır
• Krom
• Mekanik Alaşımlama
• Sıcak Presleme
• Toz Metalurjisi

Kaynakça

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