Sinan AKSÖZ, Gülizar ALTINIŞIK, Ekrem Emre ELVERİŞLİ, Bülent BOSTAN

NiTi ŞBA Tozlarında B2-R-B19' Fazlarına Sıcaklık ve Deformasyonun Etkilerinin İncelenmesi

Çalışmada, önalaşımlı NiTi şekil bellekli alaşım (ŞBA) tozlarına oda sıcaklığında (25°C), 100°C’de ve 200°C’de, farklı deformasyon oranlarına (800MPa, 1300MPa, 1600MPa, 1800MPa, 2000MPa, 2500MPa) deformasyon uygulanmıştır. Çalışmada uygulanan deformasyonun etkilerini tespit edebilmek için ise; DSC, XRD analizleri yapılmış ve optik mikroskop görüntüleri incelenmiştir. Oda sıcaklığında yapılan deformasyon neticesinde yapıda B2 ↔ R ve R ↔ B19' çift fazlı dönüşümü görülürken, 100°C’de ve 200°C’de yapılan deformasyonlar sonrası yapıda yalnızca B2 ↔ R dönüşümü görülmüştür. Numunelerin XRD analizleri incelendiğinde ise, ham tozlarda görülen B2 (östenit) fazları deformasyon oranına bağlı olarak pik şiddetleri düşmeye başlamış, en düşük B2 piki en yüksek deformasyon oranında tespit edilmiştir. XRD pik şiddetindeki düşüşün nedeni ise artan deformasyon oranına bağlı olarak, östenit pikinin şiddetinin azalmasına ve martenzit pik şiddetlerinin ise oluşmaya başlaması olarak söylenebilir.

Anahtar Kelimeler:

NiTi ŞBA, Sıcak Deformasyon, Soğuk Deformasyon

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