Stronsiyum ve stronsiyum-magnezyum katkılarının ötektiküstü Al-17Si alaşımının içyapı ve mekanik özelliklerine etkisi

Year 2019, Volume: 25 Issue: 1, 49 - 55, 26.02.2019

Ali Paşa Hekimoğlu , Gizem Ayata

Abstract

Al-17Si,
Al-17Si-0,1Sr ve Al-17Si-0,1Sr-0,6Mg alaşımları kokil kalıba döküm yöntemi ile
üretilmiştir. Alaşımların yapısal ve mekanik özellikleri üretilen alaşım külçelerinden
talaşlı imalat yöntemiyle hazırlanan numuneler üzerinde yapılan incelemeler ile
belirlenmiştir. İçyapı incelemeleri standart metalografik yöntemler ile
hazırlanan ancak dağlama yapılmayan numuneler üzerinde gerçekleştirilmiştir. İncelenen
alaşımların sertlik değerleri Brinell sertlik ölçüm yöntemi, mekanik özelikleri
ise üniversal bir çekme deneyi makinesinde yapılan testler yardımıyla belirlenmiştir.
İkili Al-17Si alaşımının içyapısının alüminyumca zengin α dendiritleri, primer
silisyum, ötektik Al-Si ve β fazlarından oluştuğu, üçlü Al-17Si-0.1Sr
alaşımının içyapısının ise ikili Al-17Si alaşımındaki fazlara ek olarak Al_xSi_ySr_z
fazını içerdiği görülmüştür. Üçlü Al-17Si-0.1Sr alaşımına %0.6 oranında yapılan
magnezyum katkısının ise bu alaşımın içyapısında Mg₂Si fazının
oluşmasına yol açtığı gözlenmiştir. Al-17Si alaşımının sertlik, akma dayanımı,
çekme dayanımı ve kopma uzaması değerleri sırasıyla 57 BSD, 93.7 MPa, 127.6 MPa ve %2.4, olarak ölçülmüştür. Bu değerler
Al-17Si-0,1Sr alaşımında 55 BSD, 95.2 MPa, 137.9 MPa ve %2.9, Al-17Si-0.1Sr-0.6Mg alaşımında ise sırasıyla 70 BSD, 123.2 MPa, 141.1 MPa ve %1.1
olarak ölçülmüştür. Stronsiyum katkısının ikili Al-17Si alaşımının sertliğini
çok az da olsa düşürdüğü, akma ve çekme dayanımı ile kopma uzaması değerlerini
ise iyileştirdiği görülmüştür. Magnezyum katkısının ise üçlü Al-17Si-0.1Sr
alaşımının akma ve çekme mukavemetini önemli ölçüde artırdığı ancak, kopma
uzamasını azalttığı belirlenmiştir. Stronsiyum ve stronsiyum-magnezyum
katkılarının Al-17Si alaşımının mekanik özelliklerine etkisi alaşımların
yapısal özelliklerine dayandırılarak açıklanmıştır.

Keywords

Al-17Si esaslı alaşımlar, İçyapı, Mekanik özellikler

Effect of strontium and strontium-magnesium additions on the microstructure and mechanical properties of hypereutectic Al-17Si alloy

Abstract

Al-17Si, Al-17Si-0,1Sr and Al-17Si-0.1Sr-0,6Mg alloys were produced by
permanent mold casting method. The structural and mechanical properties of the
alloys were determined by the investigations carried out on specimens prepared
by machining of the produced alloy ingots. The microstructural examinations
were carried out on specimens prepared by standard metallographic methods but
without etching. Their hardness and mechanical properties ​​were determined by
Brinell hardness measurement method and universal tensile tests, respectively.
The microstructure of the binary Al-17Si alloy consisted of aluminum-rich α dendrites, primary silicon, eutectic Al-Si and βphases. Ternary
Al-17Si-0.1Sr alloy contained Al_xSi_ySr_z phase
in addition to phases in the binary Al-17Si alloy. It was observed that the
0.6% magnesium addition to the ternary Al-17Si-0.1Sr alloy cause to form of Mg₂Si
phase in the microstructure of this alloy. The values of the hardness, yield
strength, tensile strength and elongation to fracture of Al-17Si alloy were
measured as 57 BSD, 93.7 MPa, 127.6 MPa and 2.4%, respectively. These values
were measured as 55 BSD, 95.2 MPa, 137.9 MPa and 2.9% in Al-17Si-0.1Sr alloy and 70 BSD, 123.2 MPa, 141.1 MPa and
1.1% in Al-17Si-0.1Sr-0.6Mg alloy. The addition of strontium reduced the
hardness of the binary Al-7Si alloy to a lesser degree but improved the yield
and tensile strength and elongation to fracture values. Magnesium addition
significantly increased the yield and tensile strength of the ternary
Al-17Si-0.1Sr alloy but decreased their elongation to fracture. The effects of
strontium and strontium-magnesium additions on the mechanical properties of the
Al-17Si alloy were discussed in terms of their structural properties. 

Keywords

Al-17Si based alloys, Microstructure, Mechanical properties

References

• Kaufman JG, Rooy EL. Aluminum Alloy Castings Properties, Processes and Applications, Materials Park, OH, USA, ASM International, 2004.
• Davis JR. Alloying: Understanding the Basics, Materials Park, OH, USA, ASM International, 2001.
• Türk Standardları Enstitüsü. “Alüminyum ve Alüminyum Alaşımları-Dökümler-Kimyasal Bileşim ve Mekanik Özellikler”. Ankara, Türkiye, 1706, 2010.
• Okamoto H, Schlesinger ME, Mueller EM. ASM Handbook Volume 3: Alloy Phase Diagrams. Materials Park, OH, USA, ASM International, 2016.
• Kaygısız Y, Maraşlı N. “Microstructural, mechanical and electrical characterization of directionally solidified Al-Si-Mg eutectic alloy”. Journal of Alloys and Compounds, 618, 197-203, 2015.
• Birol Y. “Effect of silicon content in grain refining hypoeutectic Al-Si foundry alloys with boron and titanium additions”. Materials Science and Technology, 28(4), 385-389, 2012.
• Kotadia HR, Das A. “Modification of solidification microstructure in hypo-and hyper-eutectic Al-Si alloys under high-intensity ultrasonic irradiation”. Journal of Alloys and Compounds, 620, 1-4, 2015.
• Darlapudi A, McDonald SD, Terzi S, Prasad A, Felberbaum M, StJohn DH. “The influence of ternary alloying elements on the Al-Si eutectic microstructure and the Si morphology”. Journal of Crystal Growth, 433, 63-73, 2016.
• Chen Z, Wang T, Gao L, Fu H, Li T. “Grain refinement and tensile properties improvement of aluminum foundry alloys by inoculation with Al-B master alloy”. Materials Science and Engineering A, 553, 32- 36, 2012.
• Shi W, Gao B, Tu G, Li S, Hao Y, Yu F. “Effect of neodymium on primary silicon and mechanical properties of hypereutectic Al-15%Si alloy”. Journal of Rare Earths, 28, 367-370, 2010.
• Birol Y. “Impact of grain size on mechanical properties of AlSi7Mg0.3 alloy”. Materials Science and Engineering A, 559, 394-400, 2013.
• Huter P, Renhart P, Oberfrank S, Schwab M, Grün F, Stauder B. “High-and low-cycle fatigue influence of silicon, copper, strontium and iron on hypo-eutectic Al-Si-Cu and Al-Si-Mg cast alloys used in cylinder heads”. International Journal of Fatigue, 82, 588-601, 2016.
• Hwang JY, Doty HW, Kaufman MJ. “The effects of Mn additions on the microstructure and mechanical properties of Al-Si-Cu casting alloys”. Materials Science and Engineering A, 488, 496-504, 2008.
• Alemdağ Y, Beder M. “Dry sliding wear properties of Al-7Si-4Zn-(0-5)Cu alloys”. Journal of the Balkan Tribological Association, 21, 154-165, 2015.
• Gholizadeh R, Shabestari SG. “Investigation of the effects of Ni, Fe, and Mn on the formation of complex intermetallic compounds in Al-Si-Cu-Mg-Ni alloys”. Metallurgical and Materials Transactions A: Physical Metallurgy and Materials Science, 42, 3447-3458, 2011.
• Alemdağ Y, Beder M. “Microstructural, mechanical and tribological properties of Al-7Si-(0-5) Zn alloys”. Materials and Design, 63, 159-167, 2014.
• Meng Y, Cui J, Zhao Z, Zuo Y. “Effect of vanadium on the microstructures and mechanical properties of an Al-Mg-Si-Cu-Cr-Ti alloy of 6XXX series”. Journal of Alloys and Compounds, 573, 102-111, 2013.
• Shaha SK, Czerwinski F, Kasprzak W, Friedman J, Chen, DL. “Microstructure and mechanical properties of Al-Si cast alloy with additions of Zr-V-Ti”. Materials and Design, 83, 801-812, 2015.
• Shaha SK, Czerwinski F, Kasprzak W, Chen DL. “Work hardening and texture during compression deformation of the Al-Si-Cu-Mg alloy modified with V, Zr and Ti”. Journal of Alloys and Compounds, 593, 290-299, 2014.
• Chen Z, Kang H, Fan G, Li J, Lu Y, Jie j, Zhang Y, Li T, Jian X, Wang T. “Grain refinement of hypoeutectic Al-Si alloys with B”. Acta Materiala, 120, 168-178, 2016.
• Alipour M, Azarbarmas M, Heydari F, Hoghoughi M, Alidoost M, Emamya M. “The effect of Al-8B grain refiner and heat treatment conditions on the microstructure, mechanical properties and dry sliding wear behavior of an Al-12Zn-3Mg-2.5Cu aluminum alloy”. Materials and Design, 38, 64-73, 2012.
• Timelli G, Camicia G, Ferraro S. “Effect of grain refinement and cooling rate on the microstructure and mechanical properties of secondary Al-Si-Cu alloys”. Journal of Materials Engineering and Performance, 23, 611-621, 2014.
• Cai Z, Wang R, Zhang C, Peng C, Xie L, Wang L. “Characterization of rapidly solidified Al-27Si hypereutectic alloy: Effect of solidification condition”. Journal of Materials Engineering and Performance, 24, 1226-1236, 2015.
• Liao H, Sun Y, Sun G. “Correlation between mechanical properties and amount of dendritic-Al phase in as-cast near-eutectic Al-11.6%Si alloys modified with strontium”. Materials Science and Engineering A, 335, 62-66, 2002.
• Xu C, Wang F, Mudassar H, Wang C, Hanada S, Xiao W, Ma C. “Effect of Sc and Sr on the eutectic Si morphology and tensile properties of Al-Si-Mg alloy”. Journal of Materials Engineering and Performance, 26(4), 1605-1613, 2017.
• Sjölander E, Seifeddine S. “Optimisation of solution treatment of Al-Si-Cu alloys”. Materials and Design, 31, 544-549, 2010.
• Toda H, Nishimura T, Uesugi K, Suzuki Y, Koboyashi M. “Influence of high-temperature solution treatments on mechanical properties of an Al-Si-Cu aluminum alloy”. Acta Materialia, 58, 2014-20251, 2010.
• Yıldırım M, Özyürek D. “The effects of Mg amount on the microstructure and mechanical properties of Al-Si-Mg alloys”. Materials and Design, 51, 767-774, 2013.
• Caceres CH, Davidson CJ, Griffiths JR, Wang QG. “The effect of Mg on the microstructure and mechanical behavior of Al-Si-Mg casting alloys”. Metallurgical and Materilas Transactions A, 30A, 2611-2618, 1999.
• Ayata G. Bor, Stronsiyum ve/veya Magnezyum Katkılarının Al-Si Alaşımlarının Yapısal Ve Mekanik Özelliklerine Etkisi. Yüksek Lisans Tezi, Recep Tayyip Erdoğan Üniversitesi, Fen Bilimleri Enstitüsü, Rize, Türkiye, 2018.
• Nogita K, McDonald SD, Dahle AK. “Effects of boron-strontium interactions on eutectic modification in Al-10 mass %Si alloys”. Materials Transactions, 44, 692-695, 2013.
• Nogita K, Dahle AK. “Determination of eutectic solidification mode in Sr-modified hypoeutectic Al-Si alloys by EBSD”. Materials Transactions, 42, 207-214, 2001.
• Savaşkan T, Hekimoğlu AP. “Relationships between mechanical and tribological properties of Zn-15Al-based ternary and quaternary alloys”. International Journal of Materials Research, 107(7), 646-652, 2016.
• Lebyodkin M, Deschamps A, Brkchet Y. “Influence of second-phase morphology and topology on mechanical and fracture properties of Al-Si alloys”. Materials Science and Engineering A, 234/236, 481-484, 1997.
• Lados DA, Apelian D. “Relationships between microstructure and fatigue crack propagation paths in Al-Si-Mg cast alloys”. Engineering Fracture Mechanics, 75, 821-832, 2008.
• Wu Z, Curtin WA. “The origins of high hardening and low ductility in magnesium”. Nature, 526, 62-75, 2015.
• Zhou J, Duszczyk J. “Fracture features of a silicon-dispersed aluminium alloy extruded from rapidly solidified powder”. Journal of Materials Science, 25, 4541-4548, 1990.
• Li Q, Xia T, Lan Y, Zhao W, Fan L, Li P. “Effect of rare earth cerium addition on the microstructure and tensile properties of hypereutectic Al-20%Si alloy”. Journal of Alloys and Compounds, 562, 25-32, 2013.
• Xu CL, Wang HY, Yang YF, Jiang QC. “Effect of Al-P-Ti-TiC-Nd2O3 modifier on the microstructure and mechanical properties of hypereutectic Al-20 wt.%Si alloy”. Materials Science and Engineering-A, 452-453, 341-346, 2007.