Cavitation formation and its minimization during superplastic forming of Inconel alloy 718SPF

Book · Sun Dec 31 04:00:00 EST 1995

OSTI ID:194192

Smith, G D; Flower, H L ^[1]

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1. Inco Alloys International, Inc., Huntington, WV (United States)

Superplastic forming of aluminum- and titanium-based alloys has become a significant manufacturing method for aerospace engine and fuselage components. Largely overlooked by design engineers is the applicability of fine-grained INCONEL{reg_sign} alloy 718SPF{trademark} to this process. This paper seeks to show the compatibility of this alloy to current superplastic forming practice and equipment. Processing parameters are presented based on laboratory data. INCONEL alloy 718SPF can be superplastically formed at 954 C (1,750 F) using flow stresses generally less than 72 MPa (10.4 psi) at an initial strain rate of 1.3 {times} 10{sup {minus}3} s{sup {minus}1} and < 28 MPa (4 psi) at 1.3 {times} 10{sup {minus}4} s{sup {minus}1}. The elongation to failure increases markedly with decreasing strain rate, exceeding 350% at an initial strain rate of 1.3 {times} 10{sup {minus}3} s{sup {minus}1}, 450% at 1.3 {times} 10{sup {minus}4} s{sup {minus}1} and 750% at 3.3 {times} 10{sup {minus}5} s{sup {minus}1}. Laboratory data are used to calculate m values (a measure of strain rate sensitivity) which increase from 0.28 at an initial strain rate of 1.3 {times} 10{sup {minus}3} s{sup {minus}1}, to 0.45 at 1.3 {times} 10{sup {minus}4} s{sup {minus}1} and to 0.83 at 3.3 {times} 10{sup {minus}5} s{sup {minus}1}.

• OSTI ID: 194192
• Report Number(s): CONF-950201--; ISBN 0-87339-300-7
• Country of Publication: United States
• Language: English

Related Subjects

33 ADVANCED PROPULSION SYSTEMS
36 MATERIALS SCIENCE
AGING
AIRCRAFT COMPONENTS
CHEMICAL COMPOSITION
ELONGATION
EXPERIMENTAL DATA
GRAIN GROWTH
GRAIN SIZE
INCONEL 718
MATERIALS
MATERIALS WORKING
METALLOGRAPHY
POROSITY
STRAIN RATE
STRESSES
TENSILE PROPERTIES