Savaşkan, T.; Azaklı, Z.; Tan, H.O.

To study the influence of nickel addition on the microstructure, mechanical and lubricated wear properties of Zn-40Al-2Cu alloy, one ternary and five quaternary Zn-40Al-2Cu-(0.5-2.5)Ni alloys were made by permanent mold casting. The wear behavior of these alloys was studied using a block-on-cylinder type test machine, after examining their microstructural and mechanical features. The microstructure of Zn-40Al-2Cu alloy was comprised of aluminum-rich α dendrites and a eutectoid α+η phase mixture. The addition of nickel caused the formation of intermetallic Al3Ni particles in the microstructure of this alloy. As the nickel content of alloys increased their hardness, friction coefficient, working temperature, and average surface roughness increased to certain extents but their strength, ductility, impact resistance, and wear volume decreased. However, the values of their wear volume and average surface roughness exhibited opposite changes with increasing nickel content. The worn surfaces of Zn-40Al-2Cu-Ni alloys were observed to be characterized by smearing and scratching marks. Furthermore, the wear and mechanical properties of these alloys were correlated, and the results were discussed in terms of their microstructural features. Finally, it may be concluded that the nickel addition adversely affects the ductility of Zn-40Al-2Cu alloy but increases its wear resistance.

Çelik, İ.; Eroğlu, H.

Metallic biomaterials used in making hip prosthesis are required to meet expectations in terms of fatigue strength, corrosion resistance, wear resistance, cost and biocompatibility. It is also desirable that the modulus of elasticity they possess is close to the level of the possible bone. Metallic biomaterials face the problem of ion release even though they meet the criteria mentioned above. As a result, the choice of metallic material to be preferred in the manufacture of hip prosthesis can be made by evaluating all these criteria among themselves and by the performances of biomaterials to be compared according to these criteria. In this study, firstly the criteria expected from the metals to be used as biomaterials have been determined. Expert opinions about the subject and criteria determined in accordance with the studies in the literature by using analytical hierarchy process have been graded according to each other. Afterwards, selection of the most appropriate material was ensured by making the order of importance according to the criteria of the candidate materials.