Fatigue crack growth and closure in aluminum alloys

Journal Article · Sun May 15 04:00:00 EDT 1994 · Scripta Metallurgica et Materialia; (United States)

DOI:https://doi.org/10.1016/0956-716X(94)90269-0· OSTI ID:7236557

Bull, C ^[1]; Hermann, R ^[2]

---

1. Brown Univ., Providence, RI (United States). Div. of Engineering
2. Open Univ., Milton Keynes (United Kingdom). Faculty of Technology

In earlier publications on fatigue and crack closure in aluminum alloys, it was shown that crack closure and related crack shielding mechanisms can be studied successfully by applying the shadow optical method. These studies indicated that at least one mechanism--plasticity induced crack closure--can be identified quantitatively from measurements of both the transverse diameter of the caustic and compliance measurements. The driving force, [Delta]K, was shown to be reduced in or near the fatigue threshold of the alloy but this effect was shown to be dependent on the range of [Delta]K and the crack length. The conclusions drawn from these studies were that in addition to determining that part of the fatigue cycle over which the crack is actually open, the shadow optical method allowed--for the first time--an accurate interrogation of K in the entire fatigue cycle. This knowledge of crack closure gained by the shadow optical method will be applied to the fatigue and crack closure behavior of metal-matrix composites (MMC) reinforced with several different volume fractions of SiC-particulates. The present work outlines the basic techniques used for determining crack closure for an un-reinforced alloy which served as a control for the MMC results to follow. An account will be presented of how the present results compare to those obtained by traditional method of closure analysis.

• OSTI ID: 7236557
• Journal Information: Scripta Metallurgica et Materialia; (United States), Journal Name: Scripta Metallurgica et Materialia; (United States) Vol. 30:10; ISSN 0956-716X; ISSN SCRMEX
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
360103* -- Metals & Alloys-- Mechanical Properties
ALLOYS
ALUMINIUM ALLOYS
COMPOSITE MATERIALS
CRACK PROPAGATION
DATA
DATA ANALYSIS
EXPERIMENTAL DATA
FATIGUE
INFORMATION
MATERIALS
MECHANICAL PROPERTIES
NUMERICAL DATA