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Creep‐Induced Residual Stress Strengthening in a Nicalon‐Fiber‐Reinforced BMAS‐Glass‐Ceramic‐Matrix Composite
Author(s) -
Widjaja Sujanto,
Jakus Karl,
Ritter John E.,
LaraCurzio Edgar,
Watkins Thomas R.,
Sun Ellen Y.,
Brennan John J.
Publication year - 1999
Publication title -
journal of the american ceramic society
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.9
H-Index - 196
eISSN - 1551-2916
pISSN - 0002-7820
DOI - 10.1111/j.1151-2916.1999.tb01814.x
Subject(s) - materials science , composite material , creep , composite number , ceramic matrix composite , residual stress , stress (linguistics) , ceramic , fiber , ultimate tensile strength , matrix (chemical analysis) , compressive strength , fiber pull out , composite laminates , philosophy , linguistics
The feasibility of inducing a compressive residual stress in the matrix of a Nicalon‐fiber‐reinforced BMAS‐glass‐ceramic‐matrix composite through a creep‐load transfer treatment was studied. Specimens were crept at 1100°C under constant tensile load to cause load transfer from the matrix to the fibers, then cooled under load. Upon removal of the load at room temperature, the matrix was put into compression by the elastic recovery of the fibers. This compressive residual stress in the matrix increased the room‐temperature proportional limit stress of the composite. The increase in the proportional limit stress was found to be dependent upon the applied creep stress, with an increase in creep stress resulting in an increase in the proportional limit stress. Acoustic emission results showed that the onset of significant matrix cracking correlated closely to the proportional limit stress. Changes in the state of residual stress in the matrix were supported by X‐ray diffraction results. Fracture surfaces of all specimens exhibited fiber pullout behavior, indicating that the creep‐load transfer process did not embrittle the fiber/matrix interface.