National Aeronautics and Space Administration
Date of this Version
2010
Citation
Materials Science and Engineering A 527 (2010) 2129–2135; doi:10.1016/j.msea.2009.11.064
Abstract
Metallic Cu–8%Cr, Cu–26%Cr, Cu–8%Cr–1%Al, NiAl and NiCrAlY monolithic coatings were fabricated by
vacuum plasma spray deposition processes for thermal expansion property measurements between 293
and 1223 K. The corrected thermal expansion, (∆L/L0)thermal, varies with the absolute temperature, T, as
( ∆L ) = A(T-293)3 + B(T-293)2 + C(T -293) + D
(L0)thermal
where A, B, C and D are regression constants. Excellent reproducibility was observed for all of the
coatings except for data obtained on the Cu–8%Cr and Cu–26%Cr coatings in the first heat-up cycle, which
deviated from those determined in the subsequent cycles. This deviation is attributed to the presence of
residual stresses developed during the spraying of the coatings, which are relieved after the first heat-up
cycle. In the cases of Cu–8%Cr and NiAl, the thermal expansion data were observed to be reproducible
for three specimens. The linear expansion data for Cu–8%Cr and Cu–26%Cr agree extremely well with
rule of mixture (ROM) predictions. Comparison of the data for the Cu–8%Cr coating with literature data
for Cr and Cu revealed that the thermal expansion behavior of this alloy is determined by the Cu-rich
matrix. The data for NiAl and NiCrAlY are in excellent agreement with published results irrespective of
composition and the methods used for processing the materials. The implications of these results on
coating GRCop-84 copper alloy combustor liners for reusable launch vehicles are discussed