Ataş, Mehmet Şahin

Profile URL
https://hdl.handle.net/20.500.13091/11564
Name Variants
Ataş, M. Ş. Atas, Mehmet Sahin Atas, Mehmet S. Atas, M. S. Ataş, Mehmet Ş.
Job Title
Email Address
msatas@ktun.edu.tr
Main Affiliation
02.11. Department of Metallurgical and Materials Engineering
Status
Current Staff
Website
ORCID ID
0000-0001-8361-5913
Scopus Author ID
57194687259
Turkish CoHE Profile ID
0EB30BBD416F1818
Google Scholar ID
Sov33UcAAAAJ
WoS Researcher ID
T-6503-2017

Research Topics

Domains
Physical Sciences
Fields
EngineeringMaterials Science
Subfields
Aerospace EngineeringMechanical EngineeringCeramics and Composites
Specific Research Areas
High-Temperature Coating Behaviors
High Temperature Alloys and Creep
Intermetallics and Advanced Alloy Properties
Aluminum Alloys Composites Properties
Advanced ceramic materials synthesis

Sustainable Development Goals

NO POVERTY1
NO POVERTY
0
Research Products
ZERO HUNGER2
ZERO HUNGER
0
Research Products
GOOD HEALTH AND WELL-BEING3
GOOD HEALTH AND WELL-BEING
0
Research Products
QUALITY EDUCATION4
QUALITY EDUCATION
0
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GENDER EQUALITY5
GENDER EQUALITY
0
Research Products
CLEAN WATER AND SANITATION6
CLEAN WATER AND SANITATION
0
Research Products
AFFORDABLE AND CLEAN ENERGY7
AFFORDABLE AND CLEAN ENERGY
0
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DECENT WORK AND ECONOMIC GROWTH8
DECENT WORK AND ECONOMIC GROWTH
0
Research Products
INDUSTRY, INNOVATION AND INFRASTRUCTURE9
INDUSTRY, INNOVATION AND INFRASTRUCTURE
0
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REDUCED INEQUALITIES10
REDUCED INEQUALITIES
0
Research Products
SUSTAINABLE CITIES AND COMMUNITIES11
SUSTAINABLE CITIES AND COMMUNITIES
3
Research Products
RESPONSIBLE CONSUMPTION AND PRODUCTION12
RESPONSIBLE CONSUMPTION AND PRODUCTION
0
Research Products
CLIMATE ACTION13
CLIMATE ACTION
0
Research Products
LIFE BELOW WATER14
LIFE BELOW WATER
0
Research Products
LIFE ON LAND15
LIFE ON LAND
0
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PEACE, JUSTICE AND STRONG INSTITUTIONS16
PEACE, JUSTICE AND STRONG INSTITUTIONS
0
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PARTNERSHIPS FOR THE GOALS17
PARTNERSHIPS FOR THE GOALS
0
Research Products
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Documents

8

Citations

47

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Publication Collaboration

Affiliation Name Count
Konya Technical University 22
Necmettin Erbakan University 4
Niğde Ömer Halisdemir Üniversitesi 3
Selçuk University 3
Van Yüzüncü Yıl Üniversitesi 2
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Data obtained from OpenAlex
Scholarly Output

22

Articles

20

Views / Downloads

48/67

Supervised MSc Theses

1

Supervised PhD Theses

1

WoS Citation Count

69

Scopus Citation Count

71

Patents

0

Projects

0

WoS Citations per Publication

3.14

Scopus Citations per Publication

3.23

Open Access Source

9

Supervised Theses

2

JournalCount
Nuclear Instruments and Methods in Physics Research, Section B: Beam Interactions with Materials and Atoms2
Radiation Physics and Chemistry2
Journal of Materials Engineering and Performance2
International Journal of Metalcasting1
JOURNAL OF ALLOYS AND COMPOUNDS1
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Scholarly Output Search Results

Now showing 1 - 10 of 22
  • Article
    Effect of High-Dose Gamma Irradiation on the Microstructure, Mechanical and Radiation Shielding Performance of Nano-Er2O3 Reinforced Al7075–B4C Hybrid Composites
    (Pergamon-Elsevier Science Ltd, 2026-10-01) Akkaş, Ayhan; Ataş, Mehmet Şahin; Savkliyildiz, Lyas; Şavklıyıldız, İlyas; Arıcı, Gökhan; Sahin Atas, Mehmet; Demir, Hikmettin; Bölükdemir, Mustafa Hicabi
    This study focuses on the fabrication and characterization of B4C and nano-Er2O3-reinforced Al7075 metal matrix composites, with compositions of Al7075-(10-n)B4C-nEr(2)O(3) (n = 0, 2, 4, 6 wt%). The composites were produced through high-energy ball milling, cold isostatic pressing, and sintering at 550 degrees C. Phase constitution, microstructure, and mechanical properties were examined before and after Co-60 gamma irradiation at doses of 50, 100, and 200 kGy. X-ray diffraction (XRD) analyses revealed alpha-Al as the primary phase in all compositions. An increase in Er2O3 content resulted in peak broadening and slight 2 theta shifts, indicating enhanced lattice strain, increased defect density, and grain refinement. No intermetallic reaction phases formed between the Al7075 matrix and B4C/Er2O3 reinforcements. SEM/EDS observations showed that the composite containing 4-Er2O3 and 6-B4C exhibited the most homogeneous reinforcement distribution, lowest porosity, and superior sintering integrity, while 6-Er2O3 led to particle agglomeration and microstructural degradation. Vickers microhardness measurements demonstrated that Er2O3 addition and moderate gamma doses (<= 100 kGy) enhanced hardness through dispersion and radiation hardening, but a significant decrease in hardness occurred at 200 kGy due to radiation-induced pore and crack formation. Gamma shielding performance was experimentally evaluated using Am-241 (59.5 keV) and Cs-137 (662 keV) sources in narrow-beam geometry and validated by PHITS Monte Carlo simulations. Increasing Er2O3 content improved the linear attenuation coefficient by approximately similar to 63% at 59.5 keV and similar to 11% at 662 keV, despite a decrease in B4C content. Overall, the 4-Er2O3 composite is a promising lightweight structural gamma-shielding material for aerospace and nuclear applications.
  • Article
    Influence of Er2O3 Addition on Flash Sintering Behavior, Phase Evolution, and Mechanical Properties of B4C-10SiC Ceramics
    (Springer, 2026-03-30) Atas, Mehmet Sahin; Ak, Oguzhan
    The mechanical, thermal, and electrical characteristics of B4C-10SiC composites with varying concentrations of Er2O3 added by flash sintering were examined in this work. The initial current transition temperature, the temperature at which the current transition rate begins, and the maximum current temperature were analyzed in detail. With the addition of Er2O3, the maximum current transition temperature decreased from 613 to 545 degrees C, accelerating the sintering mechanism. XRD analyses revealed that phase formation was limited to low Er2O3 concentrations, while crystallization increased at higher concentrations. SEM images showed that 1 wt.% Er2O3 provided the most homogeneous microstructure and enhanced densification. Hardness analyses indicated that 3 wt.% Er2O3 achieved the highest hardness of 2827.2 HV. Although the hardness increased with 3 wt.% Er2O3, phase separations and microstructural irregularities were observed. The results demonstrated that the optimum Er2O3 content is 1 wt.%, which optimizes the sintering mechanism and improves mechanical properties. Excessive Er2O3 addition was found to disrupt microstructural homogeneity, negatively affecting material properties. In addition, Thermo-Calc software was utilized to construct the solidification curve of the B4C-10SiC-3Er(2)O(3) system and to evaluate the B4C-SiC phase diagram, providing thermodynamic insights into the phase evolution. Ultimately, multicomponent carbide and oxide composites can be consolidated concomitantly via flash sintering which makes this study novel.
  • Article
    Citation - WoS: 2
    Citation - Scopus: 2
    Microstructural Evolution and Coarsening in Ni-Al Model Superalloys With Nano Γ′-Precipitates: an Experimental and Thermodynamic Investigation
    (Springernature, 2024-07-24) Ataş, Mehmet Şahin; Cengiz, Rabia; Yıldırım, Mehmet
    The microstructural evolution, including precipitate size, volume fraction, morphology, and distribution of gamma ' precipitates in the gamma matrix, as well as coarsening kinetics and hardness of Ni-11Al-9Cr, Ni-11Al-9Cr-2Co, and Ni-11Al-9Cr-4Co model superalloys aged at 800 degrees C for 1-256 h, are studied experimentally and thermodynamically. Thermodynamic investigations show that Co addition slightly changes the solvus, solidus, and liquidus temperatures. For early aging times (t < 64 h), spheroidal gamma '-precipitates with particle sizes smaller than 60 nm is observed for all compositions. For the longer aging times (t >= 64 h), the gamma '-precipitates become slightly coarser, the precipitate radius increases, and their morphology starts to transform into cuboidal. For almost all compositions and aging conditions, the average gamma '-precipitate radius is lower than 100 nm. Co refines the microstructure, reduces the coarsening rate, and increases the microhardness. Among investigated compositions, Ni-11Al-9Cr-4Co superalloy exhibits the lowest gamma '-precipitate size, slowest coarsening rate and highest microhardness.
  • Article
    Spectrophotometer-Based Novel Models for Detection of Fire Damage in Stone Monuments
    (Springer Heidelberg, 2026-04-20) Hatir, Mehmet Ergun; Atas, Mehmet Sahin; Ince, Ismail; Korkanc, Mustafa
    Fires are one of the biggest threats to the transfer of cultural heritage to future generations. Sudden thermal differences endanger cultural heritage by causing changes in the chemical and physical properties of stones. Rapidly estimating the changes in the physical and strength properties of building stones after a fire is vital for restoration work. Colour changes occurring in building blocks after chemical processes can be an important tool in predicting the physical properties of the blocks. For this purpose, the samples were first subjected to heat treatment at different temperatures in a laboratory environment, and non-destructive tests (P-wave velocity, spectrophotometer, and Karsten tube) were performed for each stage. Colour differences occurring in the samples after heat treatment were digitized using a spectrophotometer. The relationships between these data and the physical properties obtained in the laboratory were modelled. Then, using the proposed models, the temperatures to which the in-situ building blocks were exposed during the fire and the changes in their physical properties were determined. Finally, the correlation between the predicted values and on-site non-destructive testing (NDT) measurements was examined. According to the findings obtained from the study, it was revealed that the proposed method predicts the change in physical properties due to in-situ fire temperature with a high correlation coefficient.
  • Doctoral Thesis
    Ni-al-x (x = Nb ve Y) Esaslı Süperalaşımların Mikroyapısal Özelliklerinin ve Oksidasyon Davranışlarının İncelenmesi
    (Konya Teknik Üniversitesi, 2021) Ataş, Mehmet Şahin; Yıldırım, Mehmet
    Nikel esaslı süperalaşımlar, yüksek korozyon-oksidasyon direnci, yüksek sürünme dayanımı ve üstün yüksek sıcaklık mekanik özelliklerinden ötürü yüksek sıcaklık uygulamalarında kullanılan önemli malzemelerdir. Bu üstün fiziksel ve mekanik özellikler, Ni esaslı süperalaşımları havacılık endüstrisi, termik santraller, nükleer enerji santralleri ve kimyasal tesisler gibi özel uygulamalar için cazip bir yüksek sıcaklık yapısal malzeme sınıfı haline getirmiştir. Nikel esaslı süperalaşımların olağanüstü fiziksel ve mekanik özellikleri, YMK yapıdaki ?-(Ni) matris içinde dağılmış L12 düzenindeki ??-(Ni3Al) çökeltilerinden oluşan çift fazlı mikroyapılarından kaynaklanmaktadır. Hem ?-(Ni) matris fazı hem de ??-(Ni3Al) çökeltileri, kübik kristal yapıya sahiptir ve aralarındaki küçük kafes uyumsuzluk parametresi, uyumlu ?/?? arayüzeylerinin oluşumuyla sonuçlanmaktadır. Bununla birlikte, Ni esaslı süperalaşımlarda ?? çökeltileri, yüksek sıcaklıklarda uzun süreli yaşlandırma işlemlerinden sonra kaçınılmaz olarak irileşmektedir. ?? çökeltilerinin ara yüzey enerjisi ile elastik enerji arasındaki dengeden kaynaklanan irileşme, ? matris fazı ile ?? çökeltileri arasındaki uyumu ortadan kaldırmaktadır. ?? çökeltilerinin irileşmesi sonucu, morfolojisindeki ve boyutlarındaki değişikliklerden dolayı bu malzemelerin yüksek sıcaklık mekanik özelliklerinin ve sürünme davranışının kötüleşebileceği bilinmektedir. Yüksek sıcaklıklarda, çökelme sertleşmesinden kaynaklanan yüksek mukavemet, irileşme davranışından dolayı azalmaktadır. Nikel esaslı süperalaşımlarda, ?? çökeltilerinin irileşme davranışı ile ilgili çok az çalışma yapılmıştr. Nikel esaslı süperalaşımların, üstün mekanik özellikleri ve yüksek sürünme dayanımının yanında çalışma koşullarında yeterli oksidasyon direncine de sahip olması gerekmektedir. Yüksek sıcaklıklarda ve oksijen içeren atmosferlerdeki oksidasyon davranışı, bu malzemelerin çalışma ömrünü sınırlandırmaktadır. Nikel esaslı süperalaşımların termal döngü koşulları altındaki sürekli oksidasyonu, çatlak yayılmasını hızlandırmakta ve sonunda kırılmaya neden olmaktadır. Bu bakımdan, Ni esaslı süperalaşımlar, oksidatif bir ortama maruz kaldıklarında, yüzeylerinde yoğun, kompakt ve koruyucu oksit ürünlerinin oluşması gerekmektedir. Bu yüzden, yüksek sıcaklık mukavemeti, mikroyapısal kararlılık, oksidasyon direnci ve dökülebilirliğin en iyi kombinasyonunu sağlayan Ni esaslı bir süperalaşımın geliştirilmesi oldukça önemlidir. Yapılan literatür araştırmasında, mikroyapısal gelişim, irileşme kinetiği, mekanik özellikler ve Ni esaslı süperalaşımların oksidasyon direncini içeren kapsamlı çalışmalar bulunmamaktadır. Bu tez çalışmasında iki temel amaç hedeflenmiştir: (i) üçüncül alaşım elementi (X = Nb ve Y, n = 2 ve 4 at. %) ilavesinin Ni85Al15-nXn süperalaşımların yaşlandırma süresine bağlı olarak mikroyapısal gelişimi, irileşme kinetiği ve mikrosertliğe etkisinin incelenmesi, (ii) Ni85Al15-nXn süperalaşımların yüksek sıcaklık oksidasyon davranışlarının alaşım elementi ilavesi ve uygun ısıl işlem yöntemleri ile geliştirilmesidir. Bu amaçla Ni85Al15-nXn süperalaşımları üretilmiş ve çeşitli tekniklerle karakterize edilmiştir. Üçüncül alaşım elementi ilavesinin L12 düzenindeki ?? çökeltilerinin mikroyapısına, irileşme kinetiğine, mikrosertlik değerlerine ve yüksek sıcaklık oksidasyon davranışına etkisi hem döküm hem de ısıl işlem görmüş numunelerde detaylı olarak incelenmiştir. Üçüncül alaşım elementinin cinsi ve miktarının uygun yaşlandırma koşulları ile birlikte incelenen özelliklere önemli etkisinin olduğu saptanmıştır. Üretilen süperalaşımların mekanik özellikleri, YMK yapıya sahip ? (Ni) matris içinde dağılmış L12 düzenindeki ?? (Ni3Al) çökeltilerinin boyut ve boyut dağılımı, hacim oranı, şekli ve yönelimi ve ? (Ni) matris fazının kanal genişliğine bağlı olduğu gösterilmiştir. Çevrimsel oksidasyon testleri ve test sonrası oluşan oksit tabakası yüzeysel ve kesit analizi yapılarak incelenmiştir. Bu analizlere göre, filmin dış tabakasında NiO oluştuğu, oksidasyon/metal arayüzeyine yakın iç oksidasyon bölgesinde Al2O3 oluştuğu tespit edilmiştir.
  • Article
    Synergistic Enhancement of Gamma Radiation Shielding and Mechanical Properties in Al7075 Composites via Nano-Er2O3 Reinforcement: A Combined Experimental and PHITS Simulation Study
    (Elsevier, 2026-08-01) Dere, Erdem; Altinordu, Sena; Ozsumer, Aras; Baltaci, Bedirhan; Atas, Mehmet Sahin
    Aluminum alloys are widely used in weight-critical engineering systems; however, their intrinsically low atomic number limits their effectiveness for gamma-ray shielding. In this study, nano-Er2O3 (0-4 wt%) was incorporated into an Al7075 matrix and consolidated via a powder-metallurgy route consisting of mechanical alloying, cold isostatic pressing, and sintering (550 degrees C/4 h, Ar). Microstructural analyses reveal that 1 wt% Er2O3 provides the most homogeneous dispersion, whereas 4 wt% promotes particle clustering at interparticle/grain boundaries and increases porosity. The 1 wt% composite exhibited the most favorable densification strength balance with a relative density of 96.88% and a Vickers microhardness of 32.72 HV (HV0.2), compared to 20.44 HV for unreinforced Al7075. Gamma attenuation measurements using Am-241 (59.5 keV) and Cs-137 (662 keV), supported by PHITS Monte Carlo simulations, show a pronounced improvement in shielding performance with increasing Er2O3 content, particularly at low photon energy. The linear attenuation coefficient increased by up to 236.1% (Am-241) and 89.7% (Cs-137) for the 4 wt% composite relative to Al7075, with experimental and PHITS results agreeing within similar to 6%. Overall, nano-Er2O3 reinforced Al7075 composites offer a promising lightweight structural shielding concept for aerospace applications, where an optimum reinforcement level (approximate to 1 wt%) maximizes microstructural integrity and hardness, while higher contents further enhance attenuation for missions requiring increased low-energy gamma protection in harsh orbital environments.
  • Article
    Ni-feni3-fe3o4 Metalik Nanoalaşımların Hidrotermal Yöntemle Sentezi ve Karakterizasyonu
    (Konya Teknik Univ, 2022-12-03) Ataş, Mehmet Şahin; Altıntaş Yıldırım, Özlem; Yıldırım, Ozlem Altıntas
    Bu çalışmada, Ni-FeNi3-Fe3O4 metalik nanoalaşımlar hidrotermal yöntem kullanılarak 180 °C’de 2 saatte başarılı bir şekilde sentezlenmiştir. Sentezi gerçekleştirilen metalik nanoalaşımların yapısal ve morfolojik özellikleri X-ışını Kırınımı (XRD), Fourier Dönüşümlü Infrared Spektrofotometresi (FTIR) ve Taramalı Elektron Mikroskobu (SEM) kullanılarak karakterize edilmiştir. X-ışını Kırınım metodu sonucu elde edilen kırınım desenleri incelendiğinde yüksek şiddetli piklerin kübik kristal yapıdaki FeNi3 ve metalik Ni’e ait olduğu belirlenmiştir. Daha düşük şiddette elde edilen piklerin ise Fe3O4 yapısına ait olduğu gösterilmiştir. FTIR analizi sonucu 455,2 ve 570,9 cm-1’de elde edilen piklerin sırasıyla Fe-Ni ve Fe-O bağlarına ait karakteristik pik olduğu gösterilmiştir. SEM-EDS analizlerinden ise sentezlenen metalik nanoalaşımlar ortalama yarıçapı 3,51 μm olan küresel parçacıkların metalik Ni fazı olduğu ve yüzeylerin bir miktar FeNi3 nanoparçacıkları ile kaplandığı görülmüştür. Ortalama yarıçapı 63,33 nm olan düzensiz şekilli nanoparçacıkların ise Fe3O4 ile birlikte FeNi3 yapısında olduğu belirlenmiştir.
  • Article
    Citation - WoS: 5
    Citation - Scopus: 6
    Structural Properties and Cyclic Oxidation Behavior of Ni-Al Superalloys
    (Redakcia Kovove Materialy, 2022-10-17) Ataş, Mehmet Şahin; Yıldırım, Mehmet
    The microstructure, microhardness, and oxidation resistance of ternary model Ni-13Al--2Y(at.%) and Ni-11Al-4Y (at.%) superalloys were studied in detail. The microstructures of alloys consisted of primary gamma-Ni dendrites and residual eutectic. The Ni17Y2 intermetallic and gamma-Ni were the major constituents of the eutectic phase mixture. The microhardness value of Ni-11Al-4Y alloy was higher than that of Ni-13Al-2Y alloy because of the higher amount of relatively harder eutectic. With increasing Y concentration from 2 to 4 at.%, the mass gain, oxide scale thickness, and oxidation rate remarkably increased. For both alloys, the oxide scale was comprised of three layers: NiO as a surface layer, Al2O3 as an inner layer in the metal/oxide interface, and mixed Al/Y oxides as an internal layer. Although the studied alloys exhibited fairly good scale adherence in conjunction with almost no important scale spallation, they exhibited faster oxidation kinetics along with higher mass gains.
  • Article
    Synthesis and Characterization of Spherical Feni3 Metallic Nanoparticles Based on Sodium Dodecyl Sulfate
    (2022) Yıldırım, Özlem Altıntaş; Ataş, Mehmet Şahin
    In this work, the metallicFeNi3nanoparticles with spherical structure have been synthesized in the presence of sodium dodecyl sulfate (SDS) using the hydrothermal method at 180 °C for 2 hours. The structural and morphological of the FeNi3metallic nanoparticles were characterizedby X-ray diffraction (XRD), Fourier transforms infrared spectra (FTIR), scanning electron microscopy (SEM), and energy dispersion spectrum (EDS). As a result of XRD, the obtained metallic nanoparticles were observed to be single-phase pure stoichiometric FeNi3metallic nanoparticles with a face-centered cubic crystal structure. In the FTIR analysis, the peak obtained at 478.3 cm-1was a characteristic Fe-Ni peak. The SEM-EDS images obtained in the microstructure analysis showed that the FeNi3metallic nanoparticles produced were 169.33 nm in size and had a spherical morphology. The hydrothermal method used in the study is known to be very effective in producing metallic nanoparticles. In addition, the use of sodium dodecyl sulfate as an anionic surfactant and the realization of the reaction in ethanol/water environments reveal the innovative aspect of the study.
  • Article
    Citation - WoS: 21
    Citation - Scopus: 22
    Temporal Evolution, Coarsening Behavior and Oxidation Resistance of Ni-15al Superalloy
    (ELSEVIER SCIENCE SA, 2019-11-01) Ataş, Mehmet Şahin; Yıldırım, Mehmet
    The temporal evolution including size, amount, morphology and distribution of gamma' precipitates in gamma matrix in conjunction with coarsening kinetics and oxidation behavior of a model Ni-15Al alloy aged at 800 degrees C for 1, 4, 16, 64 and 256 h is studied in detail. The microstructure of the investigated samples consists of L1(2)-type ordered gamma' (Ni3Al) precipitates and a disordered Ni-rich gamma (FCC) matrix phase. Spheroidal-to-cuboidal-to parallelpipedic morphological transition is observed as the mean precipitate radius increases with increasing aging time. The temporal exponent p is calculated as 0.35 which agrees well with the diffusion-controlled LSW theory (p = 0.33) for coarsening of a binary alloy. However, the power law dependence of the number density (N-V) departs from the theoretical predictions which suggests a quasi-stationary coarsening. The cyclic oxidation behavior of as-cast and aged (800 degrees C for 4, 16, 64 and 256 h) Ni-15Al superalloys at 1000 degrees C in laboratory air were investigated in detail. The results showed that 4 and 16 h aged samples exhibited considerably better oxidation resistance compared to as-cast and 64 and 256 h aged samples. The oxide product is identified as NiO by X-ray diffraction (XRD) analyses. Uniform, even and adherent oxide scale formed without any void formation and important scale spallation. (C) 2019 Elsevier B.V. All rights reserved.