Reproducibility of small-strain creep tests of Ti 6242Si
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Titanium 6242Si was creep tested at 510 ‡C and 241 MPa to plastic strains of about 0.002. These conditions are common in commercial specifications for acceptance of this alloy. Nineteen specimens were extracted from four identically thermally and mechanically processed coupons from the same ingot and creep tested. The results indicate relatively poor reproducibility despite essentially identical sample preparation and specimen testing procedures. The causes of the scatter are unclear. The average creep strain of the 19 specimens after 35 h was 0.067%, and the standard deviation was 0.0367%. Significant scatter is also evident among the average properties of the four coupons. The results suggest that impurity levels and processing procedures may require adjustments to ensure relatively low expected or “average” creep strain levels (half the allowable) in some common acceptance specifications to ensure a high probability of acceptance.
Keywordscreep tests titanium alloys
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- 2.S. Ankem and S.R. Seagle, The Detrimental Effects of Iron on Creep of Ti 6242Si Alloys,Proceedings of the 5th International Titanium Conference, Munich, AIME, 1984, p 2411–2418Google Scholar
- 3.P.J. Bania, J. Hall, and L. Bidwell, The Effects of Minor Alloying Element Additions on Mechanical Properties of Ti Alloys, Interim Technical Report, AFML contract No. F33615-75-C-5089, 1975Google Scholar
- 4.K.E. Thiehsen, The Effect of Primary Alpha, Nickel and Chromium on the Creep Behavior of Ti 6242Si, M.S. thesis, Oregon State University, Corvallis, OR, 1993Google Scholar
- 5.S.A.E. Aerospace Material Specification 4976D, Society of Automotive Engineers, Warrendale, PA, 1988Google Scholar
- 6.Annual Book of ASTM Standards, 3.1, ASTM Testing Standard E696, ASTM, Philadelphia, PA, 1980, p 609Google Scholar
- 7.C.W. Schmidt,G.E. Quality Specifications S-400B, Evendale, OH, 1990, p 24–26Google Scholar