Mekanik Olarak Sentezlenen NiTi + Zn Tozlarının Karakterizasyonu ve Sinterlenelebilirliğinin Araştırılması

Year 2018, , 437 - 443, 01.06.2018

Sinan Aksöz , Bülent Bostan

https://doi.org/10.2339/politeknik.389617

Cited By: 3

Abstract

Bu çalışmada; önalaşımlı NiTi
tozları ve % 2, % 4, % 6, % 8 ve % 10 Zn toz oranları kullanılarak bilyeli
değirmende 60 dakika mekanik öğütme işlemine tabi tutulmuştur. Öğütülen NiTi +
Zn toz karışımları 750 MPa basınç altında presleme sonrası 1000°C’de 60 dakika
sinterlenmiştir. Öğütülen ve presleme sonrası sinterlenen numunelere
mikroyapısal değişiklikleri tespit etmek için; Taramalı Elektron Mikroskobu
(SEM), Element Dağılım Spektrometresi (EDS), Diferansiyel Taramalı Kalorimetre
(DSC) ve X-Ray (XRD) analizleri uygulanmıştır. NiTi + Zn toz karışımlarında
artan Zn oranına bağlı olarak, toz morfolojisinde değişiklikler tespit edilmiş
ve özellikle % 10 Zn ilave edilen tozlarda öğütme sonrası NiTi tozlarının
yüzeyini homojen bir şekilde tamamen kapladığı tespit edilmiştir. 

NiTi + Zn tozlarının 1000°C’de 60
dakika sinterleme sonrası Zn’nin sıvı faz sinterlenmesi ile yapıda NiTi
tozlarının arasında bir bağ oluşmuş ve böylece düşük sıcaklıklarda sinterlenme
işlemi gerçekleştirilebilmiştir. Ayrıca; NiTi + % 10Zn içeriği ile homojen ve
pürüzsüz bir mikro yapı elde edilmiştir.  

Keywords

Önalaşımlı NiTi tozları, ŞBA, toz metalurjisi

Investigation of Characterization and Sinterability of Mechanically Synthesized NiTi + Zn Powders

Abstract

In this study; prealloyed NiTi powders and ball mills
with 2%, 4%, 6%, 8% and 10% Zn powder ratios were subjected to mechanical
milling for 60 minutes. The milled NiTi + Zn powder mixtures were pressed under
750 MPa pressurize and then sintered at 1000°C for 60 minutes. In order to determine
the microstructural changes in the samples which were milled, pressed and then
sintered samples; SEM, EDS, DSC and XRD analyses were applied, respectively.
Changes in powder morphology were observed, depending of the increasing Zn
content in the NiTi + Zn powder mixtures and it was determined that the powders
containing 10% Zn completely covered the surface of the NiTi powders in a
homogeneous manner after milling.

Zn content in the micro structure also provided the alloy to be sintered
at low temperatures by completely filling the gaps and pores after the
sintering process at 1000°C for 60 min. In addition, a homogenous and smooth
microstructure was obtained with NiTi + 10Zn% content.

Keywords

Prealloyed NiTi powders, SMA, powder metallurgy

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