(57) Heat treated, spray formed articles are disclosed which exibit crack growth rates
and resistance to stress rupture comparable to corresponding, forged articles. The
articles are first formed by depositing molten metal droplets, e.g., of a superalloy
having a composition in weight percent of about 18-21 w/o Cr, 3.5-5 w/o Mo, 12-15
Co, 2.75-3.25 w/o Ti, 1.2-1.6 w/o Al, 0.01-0.08 w/o Zr, 0.003-0.010 w/o B, balance
generally nickel, on a substrate to form a rough article. The articles are HIP'ed
and then processed by heat treating, which includes solution, stabilization and precipitation
heat treatments. The resultant articles have fine average grain sizes compared to
forged and conventionally heat treated material, as well as yield and tensile strengths
comparable to forged material. Importantly, the articles also exhibit low crack growth
rates and stress rupture resistance, e.g., comparable to forged material, and have
an isotropic microstructure. The articles can be used in place of forged articles.
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