AVS 45th International Symposium
    Thin Films Division Monday Sessions
       Session TF-MoP

Paper TF-MoP27
Mechanical Properties and Strengthening Mechanisms of Pure Iron Implanted with Metal Ions

Monday, November 2, 1998, 5:30 pm, Room Hall A

Session: Thin Films Poster Session
Presenter: D. Yang, University of Alabama
Authors: D. Yang, University of Alabama
Q. Xue, Lanzhou Institute of Chemical Physics, China
Correspondent: Click to Email
Ion implantation can alternates surface composition and microstructures of metals dramatically, consequent change of physical and chemical properties of ion implanted layers appears as a result of it. The first noticeable effect of implantation is variation of surface residual stress and microhardness. To further understand the effect of metal ion implantation on mechanical properties and strengthening mechanisms, Cr, Mo, W, Ni, Al ion implantation into pure iron was performed on a Metal Vapor Vacuum Arc (MEVVA) source implanter at doses of 5×10@super 16@ ions/cm@super 2@, 1×10@super 17@ ions/cm@super 2@ and 3×10@super 17@ ions/cm@super 2@. The atomic concentration, element distribution, phase structure, surface residual stress and microhardness were measured by Auger Electron Spectroscopy (AES), X-ray Diffractometry and microhardness tester respectively. The relationship among the atomic radius, residual stress and hardness was studied and discussed. It was shown that the highest atomic concentrations in the implanted layers were between 6 at.% to 38 at.% depending on the elements implanted and implantation doses. The higher and bigger the implantation doses and differences in radius between pure iron and implanted element atoms are, the larger the highest atomic concentration in the implanted layers. In addition, the ion implantation resulted in residual compressive stresses of 663-957 MPa and an increase of 5%-43% in microhardness of pure iron surface. Ion implantation dose was not the only factor influencing surface stress and hardness. The decisive factor was the existing format of ion implanted element, i. e. if the implanted element existed as solid solute the residual compressive stress would be higher and the hardness would be lower; if it existed mainly as compounds then the stresses would be lower and the hardness higher.