Overview
ISO 28079:2026 - Hardmetals - Palmqvist toughness test is an international standard developed by ISO for determining the Palmqvist toughness of hardmetals and cermets. This document specifies an indentation method for measuring the toughness of metal-bonded carbides and carbonitrides-commonly referred to as hardmetals, cermets, or cemented carbides-at ambient temperature. The test calculates Palmqvist toughness from the total length of cracks produced at the corners of a Vickers hardness indentation. Designed for use in room temperature, standard laboratory environments, ISO 28079:2026 is not intended for application under corrosive conditions.
By providing a standardized approach to toughness measurements, this document helps ensure reliable quality control, material selection, and product design decisions in industries using hardmetals.
Key Topics
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Palmqvist toughness measurement
The core focus is the Palmqvist technique, which evaluates the toughness of hardmetals using crack lengths from the corners of Vickers indentations.
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Sample and surface preparation
The standard specifies detailed guidance for sample shape, flatness, polishing, and, if applicable, annealing procedures to obtain valid results.
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Calibration and equipment requirements
ISO 28079:2026 requires calibrated Vickers hardness testing machines and certified diamond indenters, ensuring measurement accuracy.
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Test procedure
The method involves applying a specified indentation load, measuring diagonal indentation lengths and associated cracks, and evaluating the resulting data for statistical reliability.
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Result analysis and reporting
Procedures for calculating and reporting Palmqvist toughness and Vickers hardness values are standardized, including requirements on measurement uncertainty and test validity.
Applications
ISO 28079:2026 helps industries leverage Palmqvist toughness testing for:
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Quality control
Consistent toughness assessments support manufacturing quality assurance for hardmetals and cermets.
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Material selection
Engineers and researchers use standardized Palmqvist data for selecting suitable hardmetal grades based on performance needs.
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Product development and design
The standard aids in evaluating materials for wear-resistant applications-such as cutting tools, mining components, and metal forming dies-where fracture resistance is critical.
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Comparative research
Academic and industrial laboratories can use the methodology to benchmark new or existing hardmetal compositions reliably.
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Regulatory and contractual compliance
Conformance with ISO 28079:2026 can be referenced in technical specifications and supply contracts to demonstrate adherence to international best practices.
Related Standards
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ISO 6507-1, ISO 6507-2, ISO 6507-3
Essential for Vickers hardness testing, verification, and calibration-integral to the Palmqvist method.
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ISO 3252
Provides vocabulary for powder metallurgy and standardized terminology relevant to hardmetals and cermets.
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Other ISO materials testing standards
Such as those for fracture mechanics and mechanical properties, complement the application of ISO 28079:2026 in comprehensive material assessment protocols.
Practical Value
Implementing ISO 28079:2026 ensures:
- Reproducible toughness measurement across laboratories and organizations
- Reduced uncertainty in comparing hardmetal products and grades
- Reliable data for material optimization in high-performance, wear-resistant applications
- Compliance with internationally recognized test methods, streamlining global trade and technical collaboration
By following the standard, manufacturers, laboratories, and end-users can achieve greater confidence in the performance of hardmetals and cermets in demanding applications.