Synthesis of surface pores in a bronze-graphite composite using electron beam surface melting
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Ductility of A1-Ru B2-based alloys is enhanced by increasing Ru content and by the addition of 0.5 at. pct B. Boron has a slight effect on the lattice parameter, an effect that is taken as implying that it lies in substitutional sites in AI47Ru53. Boron has a strong negative effect on elastic moduli; that effect is yet to be understood.
Added Boron (At. Pct) A1Ru
53/47 52/48 50/50
48/52 47/53 45/55 42/58 40/60
0
0.1
0.5
2.9934 -(0.0003)* 2.9922 (0.0002) 2.9931 -(0.0012) 2.9916 . (0.0007) 2.9915 . (0.0004) 2.9911 2.9900 (0.0006) (0.0010) .
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4
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-
-
-
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-
-
-
-
-
.
2.9902 (0.0007) . . .
2
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The author is pleased to thank R.J. Zabala for the elastic modulus measurements and D.W. Marsh for the lattice parameter determinations.
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2.9920 2.9905 2.9920 2.9893 (0.0010) (0.0008) (0.0010) (0.0009) 2,9900 (0.0010) . . . .
.
.
-
2.9903 (0.0009) 2.9915 ((3.0006)
1
2.9925 (0.0009)
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*Parentheses give standard-deviation uncertainties.
Table II.
Strains
(lib db/dc)
for Solute Atoms
Substitutional
Co Fe Ti
in A1Ru in A1Ru in AIRu
Interstitial
-0.062 -0.028 +0.043
C C N N
in in in in
martensite fcc* Fe fcc Fe hcp Ti
REFERENCES
-
+0.223 +0.249 +0.138 +0.044
1. R.L. Fleischer, R.D. Field, and C.L. Briant: Metall. Trans. A, 1991, vol. 22A, pp. 403-14. 2. R.L. Fleischer: lSlJlnt., 1991, vol. 31, pp. 1186-91. 3. D.W. McKee and R . L Fleischer: in MRS Symp. Proc., 1991, vol. 213, pp. 969-74. 4. R.L. Fleischer, C.L. Briant, and R.D. Field: MRS Symp. Proc., 1991, vol. 213, pp. 463-74. 5. R.L. Fleischer: Acta Metatt., 1963, vol. 11, pp. 203-09. 6. R.L. Fleischer: in The Strengthening of Metals, D. Peckner, ed., Reinhold, New York, NY, 1964, ch. 3, pp. 93-140. 7. P. Villars and L.D. Calvert: Pearson's Handbook of Crystallographic Data for lntermetallic Phases, ASM, Metals Park, OH, 1985, vol. 2. 8. W.B. Pearson: A Handbook of Lattice Spacings and Structures of Metals and Alloys, Pergamon, New York, NY, 1958. 9. K. Aoki and O. Izumi: 3pn. Inst. Met., 1979, vol. 43, pp. 1190-96. 10. R . L Fleischer: Acta Metall. Mater., 1993, in press.
B in A1Ru -0.008(• *Fcc = face-centered cubic.
Synthesis of Surface Pores in a Bronze-Graphite Composite Using Electron Beam Surface Melting 0.5%B
0.30
7.yo. 47:53,/
o..o o.lo 0
0
"W /
/o.% V /
O%B
A . T A U Q I R , I. SALAM, F.H. H A S H M I ,
and A.Q. K H A N
/
/ eso:o
10
I
I
20
The copper-tin-graphite composite is used to manufacture bearings, tl-41 For optimum mechanical properties and lubrication levels, the material is supposed to have approximately 25 vol pct of pores (a density of 6.5 g cm -3) uniformly distributed within it. The pores are necessary to maintain impregnated oil at the contact surface, but the strength and conductivity of the material is too poor to be used at high temperatures and pressures. The present study has shown that electron beam (EB) surface processing of the composite, having 10 pct porosity, forms pores in the near surface regions. Using this technique, the
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