ASTM B646-97

Standard Practice for Fracture Toughness Testing of Aluminum Alloys

SCOPE
1.1 This practice provides guidance for testing (a) thin products, of thicknesses equivalent to sheet that is, ([∧lt;=]0.249 in. (6.30 mm)), (b) intermediate thicknesses of plate, forgings, and extrusions, too thin for valid plane-strain fracture toughness testing but too thick for treatment as sheet, that is over 0.249 in. (6.30 mm) and up to 1 to 2 in. (25 to 50 mm), dependent upon toughness level, and (c) relatively thick products where Test Method E399 is applicable. For changes to this specification since the last issue, refer to the Summary of Changes section at the end of the standard.  
1.2 This practice addresses the problem of screening tests, recognizing the complexity and expense of making formal fracture toughness measurements on great quantities of production lots, and provides alternatives in the form of simpler, less expensive tests that may be carried out either in a research or production test laboratory.  
1.3 The values stated in inch-pound units are to be regarded as the standard.  
1.4 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use.

General Information

• Status: Historical
• Publication Date: 09-Oct-1997
• ICS: 77.120.10 - Aluminium and aluminium alloys
• Technical Committee: B07 - Light Metals and Alloys
• Drafting Committee: B07.05 - Testing

Relations

• Replaced By: ASTM B646-03 - Standard Practice for Fracture Toughness Testing of Aluminum Alloys
• Effective Date: 10-Sep-2003
• Referred By: ASTM B881-17 - Standard Terminology Relating to Aluminum- and Magnesium-Alloy Products
• Effective Date: 10-Oct-1997
• Referred By: ASTM F3122-14(2022) - Standard Guide for Evaluating Mechanical Properties of Metal Materials Made via Additive Manufacturing Processes
• Effective Date: 10-Oct-1997
• Referred By: ASTM B645-21 - Standard Practice for Linear-Elastic Plane-Strain Fracture Toughness Testing of Aluminum Alloys
• Effective Date: 10-Oct-1997

Standards Content (Sample)

NOTICE: This standard has either been superceded and replaced by a new version or discontinued.
Contact ASTM International (www.astm.org) for the latest information.
Designation: B 646 – 97
Standard Practice for
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Fracture Toughness Testing of Aluminum Alloys
This standard is issued under the fixed designation B 646; the number immediately following the designation indicates the year of
original adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. A
superscript epsilon (e) indicates an editorial change since the last revision or reapproval.
This standard has been approved for use by agencies of the Department of Defense.
INTRODUCTION
Fracture toughness is a key property for a number of aluminum alloys utilized in aerospace and
process industries, but at the current stage of development of fracture test techniques no standard
methods exist to cover a number of the product lines or dimensional ranges involved. Plane-strain
fracture toughness, K , is a keystone of the industry, but for the very tough alloys of principal interest,
Ic
valid measurements can be made only for relatively thick sections. Thus it is necessary to provide this
standard practice for uniform quality control test procedures for the industry, pointing out which
current standards are utilized in specific cases, and providing guidelines where no standards exist.
1. Scope B 645 Practice for Plane Strain Fracture Toughness Testing
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of Aluminum Alloys
1.1 This practice provides guidance for testing (a) thin
E 23 Test Methods for Notched Bar Impact Testing of
products, of thicknesses equivalent to sheet that is, (|La0.249
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Metallic Materials
in. (6.30 mm)), (b) intermediate thicknesses of plate, forgings,
E 338 Test Method of Sharp-Notch Tension Testing of
and extrusions, too thin for valid plane-strain fracture tough-
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High-Strength Sheet Materials
ness testing but too thick for treatment as sheet, that is over
E 399 Test Method for Plane-Strain Fracture Toughness of
0.249 in. (6.30 mm) and up to 1 to 2 in. (25 to 50 mm),
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Metallic Materials
dependent upon toughness level, and (c) relatively thick
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E 561 Practice for R-Curve Determination
products where Test Method E 399 is applicable. For changes
E 602 Test Method for Sharp-Notch Tension Testing with
to this specification since the last issue, refer to the Summary
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Cylindrical Specimens
of Changes section at the end of the standard.
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E 616 Terminology Relating to Fracture Testing
1.2 This practice addresses the problem of screening tests,
E 1304 Test Method for Plane-Strain (Chevron Notch)
recognizing the complexity and expense of making formal
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Fracture Toughness of Metallic Materials
fracture toughness measurements on great quantities of pro-
2.2 Other Document:
duction lots, and provides alternatives in the form of simpler,
Aluminum Association Bulletin T5, “Fracture Toughness
less expensive tests that may be carried out either in a research
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Testing of Aluminum Alloys”
or production test laboratory.
1.3 The values stated in inch-pound units are to be regarded
3. Terminology
as the standard.
3.1 The terminology and definitions in the referenced docu-
1.4 This standard does not purport to address all of the
ments are applicable to this practice.
safety concerns, if any, associated with its use. It is the
3.2 Definitions of Terms Specific to This Standard:
responsibility of the user of this standard to establish appro-
3.2.1 For purposes of this practice, the following descrip-
priate safety and health practices and determine the applica-
tions of terms are applicable in conjunction with Practice E 561
bility of regulatory limitations prior to use.
and use of the compact specimen:
2. Referenced Documents 3.2.2 K —A value of K on the R-curve based on a 25 %
R
25
secant intercept of the load-crack opening displacement test
2.1 ASTM Standards:
record and the effective crack length at that point that otherwise
B 557 Test Methods of Tension Testing Wrought and Cast
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satisfies the remaining-ligament criterion of Practice E 561.
Aluminum- and Magnesium-Alloy Products
3.2.3 K —A value of K on the R-curve based on the
R
max
maximum load value of the load-crack opening displacement
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This practice is under the jurisdiction of ASTM Committee B-7 on Light Metals
and Alloys, and is the direct responsibility of Subcommittee B07.05 on Testing.
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Current edition approved Oct. 10, 1997. Published May 1998. Originally Annual Book of ASTM Standards, Vol 03.01.
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published as B 646 – 78. Last previous edition B 646 – 94. Available from The Aluminum Association, 750 3rd Ave., New York, NY
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Annual Book of ASTM Standards, Vol 02.02. 10017.
Copyright © ASTM, 100 Barr Harbor Drive, West Conshohocken, PA 19428-2959, United States.
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NOTICE: This standard has either been superceded and replaced by a new version or discontinued.
Contact ASTM International (www.astm.org) for the lat
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