Ever wondered how the things around us get their seal of approval? Let’s talk about materials testing – the secret sauce behind everything from skyscrapers to smartphones to medical devices!

Well, imagine a world where bridges collapse and cars crumble – not a pretty picture, right? That’s why materials testing is important. It makes sure everything meets the quality standards for its intended use. 

What is Materials Testing?

Materials testing is a broad term that refers to the process of examining and analyzing the physical, chemical, biological, and mechanical properties of materials that are used for the manufacture and construction of a wide variety of items. This testing is conducted to understand how materials behave under different conditions, such as stress, temperature, pressure, and environmental factors. 

Material testing can occur as part of materials discovery and research or materials quality assessment. In the first scenario, computational methods and artificial intelligence (AI) may be used to search existing databases and create new material models before any actual testing starts. In the second scenario, testing happens after the material has been found or made to ensure it’s suitable for its intended use.

Who Performs Material Testing?

Material testing is conducted by laboratories accredited to specific standards and testing procedures. Accreditation is important to enhance standardization and reliability in the testing process and test results, thereby instilling confidence in products made from these tested materials. Organizations such as the International Organization for Standardization (ISO) and the American Society for Testing and Materials (ASTM) have established standard test methods for materials testing.

Categories of Materials Testing

There are 5 broad categories:

  1. Mechanical testing
  2. Testing for thermal characteristics
  3. Testing for electrical properties
  4. Testing for resistance to corrosion, radiation, and biological deterioration 
  5.  Nondestructive testing

Now, let us understand these categories in detail. 

1. Mechanical Testing

Structures, machines, or their parts can experience failure due to heavy loads or excessive deformation. To prevent such failures, labs assess anticipated stress levels, typically measured as load per unit area, and select materials capable of withstanding them. Stress analysis can be performed either through experimentation or mathematical modeling, which helps identify potential high-stress areas in a machine or structure. Stress analysis provides insights into the material’s actual service life and its performance when subjected to mechanical stress, aiding in predicting its behavior in real-world applications. Mechanical testing often involves destructive methods, which may alter or damage the material being tested.

What are the different types of material tests?

  • Static shear and bending tests
  • Measures of ductility
  • Hardness testing
  • Impact test
  • Fracture toughness tests
  • Creep test
  • Fatigue

2. Measurement of Thermal Characteristics

Thermal conductivity: Heat transmission within a solid material occurs through the transfer of free electrons and the vibration of atoms and molecules. This flow of heat ceases when the temperature across the solid material equalizes with that of its surrounding temperature.Laboratories measure thermal conductivity experimentally to determine how effectively a material conducts heat. This measurement involves determining temperature changes over time along the length of a bar or across the surface of flat plates. Simultaneously, the external input and output of heat from the surfaces of the bar or the edges of the plate are controlled for accurate measurement.
Thermal expansion: Heat causes the expansion of materials. Expansion is measured as the change in a unit length of a material resulting from a one-degree temperature shift. Several materials undergo minimal expansion due to heat, often less than a micrometer per one-degree temperature rise, hence microscopes are used to determine the expansion of materials.  

3. Measurement of Electrical Properties

Electrical conductivity involves the movement of free electrons through a solid body. Materials that allow free electrons to move rapidly within them are good conductors, for example, metals. Conversely, materials that restrict the free electron movement are insulators, for example, plastic. However, certain materials experience a significant increase in free electrons when heated, making them semiconductors. A few examples of semiconductors are carbon, germanium, and silicon. Conductivity is typically assessed by passing a known current at constant voltage through a known material volume and measuring electrical resistance in ohms. The total conductivity is then calculated by taking the reciprocal of the total resistance.

4. Testing for Corrosion, Radiation, and Biological Degradation

Testing for Corrosion: Corrosion testing serves to assess materials’ performance in specific environments such as heat, moisture, chemicals, radiation, electricity, biological substances, or their combinations. This testing is also performed to evaluate ways to safeguard materials against environmental degradation. Typically, corrosion testing involves immersing materials in electrolyte solutions such as 5% or 20% sodium chloride or calcium chloride in water. Alternatively, the solution may be sprayed into a chamber where materials are suspended. After exposure to the hostile environment, materials are examined for visible signs of corrosion. This process aids in understanding materials’ susceptibility to corrosion and refining strategies for protection.

Testing for Radiation: Radiation tests entail subjecting materials to electromagnetic radiation, such as X-rays, gamma rays, and radio-frequency waves, or atomic radiation, for a specific duration. This exposure may occur under robot control within a remote chamber containing nuclear fuels, after which conventional methods are employed to assess changes in material properties over time. Polymers, including organic compounds like plastic or synthetic rubber, are most affected by radiation.

Testing for Biological Degradation: These tests assess the susceptibility of organic materials to fungi, bacteria, and algae. Materials commonly affected by these biological organisms include paints, wrappers, and coatings used in buried pipelines, and storage tanks. Typically, samples of fungi, bacteria, or algae are isolated and cultured in a laboratory. Subsequently, these cultures are used to evaluate the materials’ susceptibility to biological deterioration.

5. Nondestructive Testing (NDT)

It is a test method employed to assess the properties and quality of materials or their components without damaging them. NDT is performed using techniques that employ liquids, radiation, ultrasonic sound, magnetism, and infrared, among others. Each technique has its principles and applications, but they all share the common goal of testing materials or components without causing damage. Nondestructive testing is preferred for materials that are expensive or difficult to fabricate.

The Role of a Material Testing LIMS

In the realm of material testing, a Laboratory Information Management System (LIMS) plays a vital role in streamlining processes and ensuring efficiency within material testing laboratories. A material testing LIMS supports laboratories by providing a centralized platform for managing samples, documents, test results, reports, and all other data generated by a laboratory. With a Material LIMS, laboratories can automate workflows, from sample registration to test execution and result reporting, reducing manual errors and increasing productivity. Moreover, a material testing LIMS facilitates adherence to accreditation standards, such as ISO/IEC 17025, and regulatory requirements. By integrating with analytical instruments, a LIMS enables seamless data capture directly from instruments, enabling laboratories to centrally manage data and eliminating any chances of manual manipulation of data. Furthermore, the trend and control charting functionality of a LIMS enables laboratories to perform statistical analysis and measure uncertainty.

Conclusion

Material testing stands as a cornerstone for guaranteeing the safety and reliability of products that shape our daily existence, ranging from towering structures to intricate electronic devices and life-saving medical devices. Accredited laboratories utilize a spectrum of testing methodologies to evaluate the quality and durability of materials under investigation. These include mechanical, thermal, electrical, and corrosion resistance testing, among others. In this intricate landscape, a material testing LIMS emerges as a pivotal ally, seamlessly supporting the operational intricacies of material testing laboratories and proving indispensable for any laboratory committed to delivering high-quality services.

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