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ELEVATED TEMPERATURE FRACTURE OF PARTICULATE‐REINFORCED ALUMINUM PART I: FRACTURE TOUGHNESS
Author(s) -
Somerday B. P.,
Leng Yang,
Gangloff R. P.
Publication year - 1995
Publication title -
fatigue and fracture of engineering materials and structures
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.887
H-Index - 84
eISSN - 1460-2695
pISSN - 8756-758X
DOI - 10.1111/j.1460-2695.1995.tb01418.x
Subject(s) - materials science , composite material , fracture toughness , nucleation , plasticity , microstructure , toughness , void (composites) , fracture mechanics , coalescence (physics) , plane stress , structural engineering , finite element method , chemistry , physics , organic chemistry , astrobiology , engineering
—The plane‐strain initiation and growth fracture toughnesses of powder‐metallurgy‐processed, SiC particulate‐reinforced 2009 plate were measured at temperatures from 25°C to 316°C. Initiation toughness from electrical potential monitoring ( K JICi ) is 18 MPa°m at 25°C, and is nearly constant to 220°C before decreasing sharply to 6 MPa°m at 316°C. Growth toughness, given by the tearing modulus ( T R ), is less than 3 from 25°C to 125°C, and increases dramatically above 200°C. The magnitude and temperature dependence of initiation toughness depend on detection of the critical fracture event. Standard measures of toughness K IC and K JIC exceed K JICi and increase to a plateau with increasing temperature. The fracture mode for the composite is microvoid nucleation, growth and coalescence at all temperatures. Void nucleation is associated with SiC; such particles both crack and create stress and plastic strain concentrations that rupture the interface or adjacent matrix, particularly at corners. Matrix plasticity and cavitation increase with increasing temperature. Void growth is regular at all temperatures, but limited by adjacent SiC particles. Both K JICi and T R are governed by the temperature‐dependent crack‐tip plastic stress and strain fields, and the intrinsic damage resistance of the composite microstructure.