PRODUCTION AND CHARACTERIZATION OF AISI 316L STAINLESS STEEL MATRIX, BORON CARBIDE AND CARBON NANOTUBE REINFORCED NANOCOMPOSITES BY POWDER METALLURGY
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2021-07
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info:eu-repo/semantics/openAccess
Özet
Bu çalışmada, AISI 316L paslanmaz çelik matrisli B4C ve KNT partikül takviyeli kompozit malzemeler sıcak pres yöntemi ile üretilmiş ve mikroyapı, mekanik, tribolojik ve korozyon özellikleri detaylı olarak incelenmiştir. Matris ve takviye malzemeleri toz olarak temin edilmiş ve yüksek enerjili bilyalı öğütme cihazında mekanik olarak karıştırıldıktan sonra sıcak preste sabit basınç ve sıcaklık altında sinterlenmiştir. Takviye elemanı olarak kullanılan B4C ve KNT partikülleri farklı oranlarda hem ayrı ayrı hem de birlikte ilave edilerek sinerjik etkileri incelenmiştir. B4C ve KNT takviye oranlarının artması ile kompozitlerin porozitesinde artış eğilimi görülürken, hesaplanan poroziteler %4,3 - %6,2 aralığında farklılıklar sergilemiştir. Yapılan mikroyapı incelemelerinde, taneler arası bölgelerde hem B4C ve KNT takviye partikülleri, hem de bunların demir ve krom ile reaksiyonları sonucu Fe3C ve Cr23C6 intermetaliklerinin oluştuğu görülmüştür. Sertlik ve basma testleri sonucunda 316L çeliğine farklı oranlardaki B4C ve KNT ilaveleri ile sertlikte artış elde edildiği görülmüştür. 316L çeliğinin dayanımına en büyük katkıyı hacimce %8 KNT takviyesi sağlamıştır (~%110). Artan B4C ve KNT ilaveleri, 316L paslanmaz çeliğin aşınma direncini sürekli olarak iyileştirmiştir. B4C ve KNT içeren kompozitlerin aşınma dirençleri karşılaştırıldığında ise B4C içeren kompozitlerin KNT içerenlerden bir miktar daha iyi aşınma direnci sergilediği görülmüştür. B4C ve KNT ilaveleri ile 316L’ nin pasivasyon potansiyel aralığı düşmüş ve pasivasyon kabiliyeti olumsuz yönde etkilenmiştir. B4C ilavesi 316L’ nin çukurcuk korozyon direncini KNT ilavesine göre daha az olumsuz etkilemiştir.
In this study, AISI 316L stainless steel matrix B4C and KNT particle reinforced composite materials were produced by hot press method and their microstructure, mechanical, tribological and corrosion properties were examined in detail. The matrix and reinforcing materials were supplied as powder and were sintered in hot press under constant pressure and temperature after being mechanically mixed in a high energy ball mill. The synergistic effects of B4C and KNT particles used as reinforcement elements were added separately and together in different proportions. While the amounts of B4C and KNT reinforcements increased, the porosity of composites tended to increase. The calculated porosities varied from 4.3% to 6.2%. In the microstructure studies, it was observed that Fe3C and Cr23C6 intermetallics were formed in the intergranular areas as a result of both B4C and KNT reinforcement particles and their reaction with iron and chromium. As a result of the hardness and compression tests, it was observed that the hardness increased with the addition of B4C and KNT to 316L steel at different amounts. The biggest contribution to the strength of 316L steel was made by 8 vol.% KNT (~110%). Increasing B4C and KNT additions have continuously improved the wear resistance of 316L stainless steel. When the abrasion resistance of composites containing B4C and KNT was compared, it was seen that B4C containing composites displayed slightly better wear resistance than those containing KNT. With the B4C and KNT additions, the passivation potential range of 316L has decreased and the passivation ability has been adversely affected. B4C addition affected pitting corrosion resistance of 316L less negatively than KNT addition."
In this study, AISI 316L stainless steel matrix B4C and KNT particle reinforced composite materials were produced by hot press method and their microstructure, mechanical, tribological and corrosion properties were examined in detail. The matrix and reinforcing materials were supplied as powder and were sintered in hot press under constant pressure and temperature after being mechanically mixed in a high energy ball mill. The synergistic effects of B4C and KNT particles used as reinforcement elements were added separately and together in different proportions. While the amounts of B4C and KNT reinforcements increased, the porosity of composites tended to increase. The calculated porosities varied from 4.3% to 6.2%. In the microstructure studies, it was observed that Fe3C and Cr23C6 intermetallics were formed in the intergranular areas as a result of both B4C and KNT reinforcement particles and their reaction with iron and chromium. As a result of the hardness and compression tests, it was observed that the hardness increased with the addition of B4C and KNT to 316L steel at different amounts. The biggest contribution to the strength of 316L steel was made by 8 vol.% KNT (~110%). Increasing B4C and KNT additions have continuously improved the wear resistance of 316L stainless steel. When the abrasion resistance of composites containing B4C and KNT was compared, it was seen that B4C containing composites displayed slightly better wear resistance than those containing KNT. With the B4C and KNT additions, the passivation potential range of 316L has decreased and the passivation ability has been adversely affected. B4C addition affected pitting corrosion resistance of 316L less negatively than KNT addition."
Açıklama
Anahtar Kelimeler
Paslanmaz çelik, metal matrisli kompozitler, mikroyapı, mekanik özellikler, korozyon, aşınma., Stainless steel, metal matrix composites, microstructure, mechanical properties, corrosion, wear
