Investigation of the effects of boro-sintering process on the microstructure and hardness properties of raw P/M parts

Öz

In this study; high purity iron (Fe) powders were pressed and subjected to BoroSintering (B/S) at 950 °C and 1050 °C for 4 and 6 hours in solid medium. The sintering process, which is one of the main steps in Powder Metallurgy (P/M), was carried out simultaneously with the boriding process. By this way the boriding and sintering processes (B/S) were completed in a single step and the possible oxide phases in microstructure were also decreased. After B/S process, hardness measurements were carried out by microvickers (HV0.05) method and hardness profiles and coating qualities were investigated. Samples were subjected to microstructure analyses by optical microscopy (OM) and field emission scanning electron microscopy (FESEM) and energy dispersive spectroscopy (EDS). As a result of the study, it was determined that a homogeneous microstructure could be obtained by applying B/S process to the samples produced by P/M method using high purity Fe powders. It was seen that B/S process can be applied successfully to provide the desired conditions in the microstructure from the obtained hardness profiles.

Anahtar Kelimeler

• P/M
• Boro-Sintering
• Pure iron
• FeB and Fe2 B phases

Boro-sinterleme işleminin ham T/M parçaların mikroyapı ve sertlik özelliklerine etkilerinin incelenmesi

Öz

Bu çalışmada; yüksek saflıkta demir (Fe) tozları preslenmiş ve katı ortamda 4 ve 6 saat boyunca 950°C’de ve 1050°C’de Boro-Sinterleme işlemine (B/S) tabi tutulmuştur. Toz
Metalürjisindeki (T/M) ana adımlardan biri olan sinterleme işlemi, borlama işlemi ile aynı anda gerçekleştirilmiştir. Bu sayede borlama ve sinterleme işlemleri tek adımda tamamlanmış ve mikroyapıdaki muhtemel oksit fazları da azaltılmıştır. B/S işleminden sonra sertlik ölçümleri microvickers (HV0.05) yöntemi ile yapılmış ve sertlik profilleri ve kaplama özellikleri incelenmiştir. Numuneler optik mikroskop (OM) ve alan emisyon taramalı elektron mikroskobu (FESEM) ve enerji dağıtıcı spektroskopisi (EDS) ile mikroyapı analizlerine tabi tutulmuştur. Çalışma sonucunda, yüksek saflıkta Fe tozları kullanarak T/M yöntemiyle üretilen numunelere B/S işlemi uygulanarak homojen bir mikroyapının elde edilebileceği belirlenmiştir. Elde edilen sertlik profillerinden mikroyapıda istenen koşulları sağlamak için B/S işleminin başarıyla uygulanabileceği görülmüştür.

Anahtar Kelimeler

• T/M
• Boro-Sinterleme
• Saf demir
• FeB ve Fe2 B fazları

Kaynakça

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