Microstructures from a directionally solidified NiAl-Cr eutectic deformed at room temperature

Journal Article · Fri Apr 15 00:00:00 EDT 1994 · Scripta Metallurgica et Materialia; (United States)

DOI:https://doi.org/10.1016/0956-716X(94)90540-1· OSTI ID:5188318

Chen, X F; Johnson, D R; Oliver, B F ^[1]

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1. Univ. of Tennessee, Knoxville, TN (United States). Material Science and Engineering Dept.

Directionally solidified alloys based on the NiAl-Cr eutectic have shown promise as high temperature structural materials. This eutectic is characterized by a fibrous microstructure consisting of chromium rods embedded within a NiAl matrix. The reinforcing metal phase provides improvements in the elevated temperature strength and the room temperature fracture toughness of the NiAl matrix. The fracture toughness of the NiAl-Cr eutectic is much greater than that of NiAl. The directionally solidified NiAl-Cr eutectic has a fracture toughness of approximately 18--21 MPa[radical]m while polycrystalline NiAl has a fracture toughness of 6 MPa[radical]m. Single crystals of NiAl oriented with a [001] notch plane have a fracture toughness of 8 MPa[radical]m. Recently, the fracture resistance of fibrous NiAl-refractory metal eutectics has been described by crack trapping and crack bridging mechanisms. However, mechanical property data for NiAl-Cr eutectic are sparse, especially those generated at room temperature. Typically, the fracture behavior is characterized by scanning electron microscopy (SEM) and optical microscopy. To complement these existing data, observations of the deformation and fracture behavior by transmission electron microscopy (TEM) are reported here.

• OSTI ID: 5188318
• Journal Information: Scripta Metallurgica et Materialia; (United States), Vol. 30:8; ISSN 0956-716X
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
ALUMINIUM ALLOYS
MECHANICAL PROPERTIES
MICROSTRUCTURE
CHROMIUM ALLOYS
NICKEL ALLOYS
DISLOCATIONS
FRACTURE PROPERTIES
ALLOYS
CRYSTAL DEFECTS
CRYSTAL STRUCTURE
LINE DEFECTS
360102* - Metals & Alloys- Structure & Phase Studies
360103 - Metals & Alloys- Mechanical Properties