نوع مقاله : مقاله کامل پژوهشی

نویسنده

دانشگاه آزاد اسلامی واحد کرج، دانشکده فنی مهندسی، گروه مهندسی مواد و متالورژی، کرج، ایران

چکیده

هدف از تحقیق حاضر سنتز و مطالعه ریزساختار و خواص مکانیکی داربست زیست تخریب پذیر Mg-Zn جهت کاربردهای ارتوپدی می باشد. بدین منظور، داربست های Mg-Zn حاوی  3 و 5 درصد وزنی Zn  با استفاده از ذرات اوره  به میزان 15،25 و 35 درصد حجمی توسط روش متالورژی پودر ساخته شدند و برای تعیین دمای بهینه تف جوشی، نمونه ها تحت عملیات حرارتی در دماهای مختلف 500، 550، 565  و 580 درجه سانتی گراد قرار گرفتند. سپس ترکیب شیمیایی، میکروساختار و خواص مکانیکی داربست های ساخته شده تحت بررسی قرار گرفت. مطابق نتایج، اندازه میانگین ماکروتخلخل و میکرو تخلخل های حاصل در داربست های ساخته شده به ترتیب در حدود 400-200 و کمتر از 100 میکرون می باشد. نتایج نشان داد که  تخلخل و حفرات موجود در نمونه ها به علت مناطق تمرکزدهنده تنش و کاهش سطح موثر قطعه در مقابل اعمال تنش خارجی، استحکام مکانیکی داربست ها را کاهش می دهند.همچنین با افزایش درصد Zn، از طریق مکانیزم استحکام دهی محلول جامد و پخشی، استحکام فشاری داربست های Mg-Zn  افزایش یافت. نتایج حاصل از آنالیز SEM  نیز نشان داد که با افزودن عنصر Zn ، ترکیبات بین فلزی Mg7Zn3 و MgZn می تواند تشکیل شود. نتایج آزمون پلاریزاسیون نشان داد که با افزودن 5درصد وزنی Zn در مقایسه با نمونه های حاوی 3 درصد وزنی به علت تشکیل ترکیبات بین فلزی بیشتر، مقاومت به خوردگی کاهش یافت. مطابق نتایج آزمون ارزیابی سمیت سلولی، میزان زیست پذیری داربست های حاوی 3 درصد وزنی Zn، بالاتر از نمونه ­های حاوی 5 درصد وزنی Zn بدست آمد.

کلیدواژه‌ها

عنوان مقاله [English]

Synthesis and study of microstructure, mechanical and biocompatibility properties of Mg-Zn scaffolds

نویسنده [English]

  • Zahra Sadat Seyedraoufi

Islamic Azad University, Karaj Branch , Department of Materials Engineering, Karaj, Iran

چکیده [English]

The aim of this research is to synthesize and study the microstructure and mechanical properties of biodegradable Mg-Zn scaffolds for orthopedic applications. For this purpose, Mg-Zn scaffolds containing 3 and 5 wt. % Zn were prepared using 15, 25 and 35 Vol% of urea by powder metallurgy and were subjected to heat treatment at different temperatures of 500, 550, 565, and 580 °C to determine the optimum sintering temperature. Then, the chemical composition, microstructure and mechanical properties of the scaffolds were investigated. According to the results, the average  diameter of macro- pores and micro- pores in the scaffolds are about 400-200 and less than 100 μm, respectively. The results showed that the compressive strength of Mg-Zn scaffolds increases with decreasing porosity amount. In fact, the porosity in the sample reduces the mechanical strength of the scaffold due to the stress concentrating areas and the reduction of the effective surface of scaffold against external stresses. Also, by increasing the Zn content, the strength of the Mg-Zn scaffold increases through the strength of the solid solution and dispersion strengthening. However, in all of the made scaffolds, the compressive strength is in the range of compressive strength of the human body's bone. The results of the SEM micrographs also showed that, by adding Zn, the intermetallic compounds Mg7Zn3 and MgZn could be formed. The results of polarization test showed that, by adding 5 wt.% of Zn in comparison with samples containing 3 wt%, due to the formation of more intermetallic compounds, the corrosion resistance decreased. According to the results of cytotoxicity measurement, the cell viability of scaffolds containing 3 wt% Zn was higher than those containing 5 wt% Zn.

کلیدواژه‌ها [English]

  • Magnesium biodegradable scaffold
  • Zn
  • Mechanical strength
  • Powder metallurgy
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