Ion Implanted Ti-6Al-4V
- PDF / 232,522 Bytes
- 6 Pages / 420.48 x 639 pts Page_size
- 17 Downloads / 220 Views
ION IMPLANTED Ti-6A1-4V 2
2
W. C. OLIVER', R. HUTCHINGS , J. B. PETHICA , E. L. PARADISI, Technologies Research Center, E. Hartford, CT 06108 iUnited 2 Erown Boveri Research Center, CI-5405 Baden, Switzerland
A.
J.
SHUSKUS
1
ABSTRACT Titanium and many of its alloys show very poor wear resistance considering their hardness. This together with high thermodynamic driving forces to form very hard compounds between titanium and nitrogen or carbon made titanium based alloys obvious candidates for ion implantation. In this paper the effects of similar implanted concentration profiles of nitrogen and carbon in two titanium alloys are compared. The wear behavior of pin on disk wear tests are reported along with the ultramicrohardness of the four samples.
INTRODUCTION Titanium alloys are one group of materials whose wear properties can be extensively improved through ion implantation [1-3]. It has also been shown that their fatigue properties can be improved through implantation [4]. The most effective ion for improving wear properties seems to be N; however, imPreliminary wear experiments planting with C yields better fatigue results. indicated a difference in the effectiveness of C versus N implantations and differences in how these two species affected Ti-6A1-4V with different prior heat treatments. The reasons for such effects are not obvious. TiN and TiC are both hard phases and have been found in implanted specimens [4,5]; hence, one would expect similar hardening effects for similar implantations. To investigate these questions two materials, an a alloy and an n-a alloy, were implanted with N or C such that similar atomic profiles were achieved. By studying the hardness and wear properties of these samples a better understanding of these surfaces should be obtained.
EXPERIMENTAL Implantation The two materials studied here are grade 2 commercial purity Ti and Ti-6A1-4V. They were both bar stock used in the as-received (mill annealed) condition. Samples approximately 8 mm thick were cut perpendicular to the bar axis and prepared for implantation by mechanically grinding and polishing to a one pm diamond polish. The implantation was done on a VarionExtrion 200 CF5 implanter. This implanter is equipped with cryo pumps that maintain a vacuum of 2 x 10-7 torr during implantation, thus minimizing gettering from the ambient atmosphere onto the sample. The implantation condition and the resulting calculated value of the range, range straggling and maximum atomic concentrations are shown in Table I.
Mat. Res. Soc.
Symp. Proc. Vol.
27 (1984)(Elsevier Science Publishing Co.,
Inc.
706
Implantation
2 3.84 x 10 21ions/m2 83 KeV C+ 5.92 x 10 21ions/m2
R (.Lm)
AR (/, m)
Peak concentrations atomic %
0.1769
0.0716
43.1
0.1727
0.0732
36.3
Ti implanted with N and C such that similar atomic profiles
TABLE I.
are achieved.
RESULTS AND DISCUSSION Hardness First let us consider the effects of N and C implanatation on the propFigure 1 shows the hardness versus depth erties of commercial purity Ti. profile for simi
Data Loading...
