Thermomechanical Analysis (TMA)

What is it?

Thermomechanical Analysis (TMA) measures changes in a sample’s size or position. Most commonly used for coefficient of thermal expansion measurements, it can also be used to measure shrinkage on curing, Tg, softening point, delamination temperature, or heat deflection to name a few. TMA is used in a wide range of fields, such as plastics, metals, electronics, optics, and aerospace to name just a few.

We offer over a wide range of temperatures (-180 to 1000° C):

*Not all possible specific testing methods are listed here

• Expansion or Contraction Measurement

• How much change does a material undergo when heated. Depending on the material (metal, glass, thermoplastic, thermoset) it can be positive or negative.

• Coefficient of Thermal Expansion, Linear Thermal Expansion (CTE or LTE)

• A CTE is used to understand how materials will respond to a thermal change. This becomes important when 2 dissimilar materials are in contact and is used predict what stresses may occur. A difference in thermal expansion coefficients can cause part failure and is a serious consideration in quality control and product development.

• Material Anisotropy is also an important property in the development of fibers, aerospace technologies, and other products. Due to material alignment, CTE measurement in the X, Y, or Z axes may be necessary.

• Applicable Methods:

  • ASTM D3386, E831, D696

  • ISO 11359

  • IPC-TM-650: TM 2.4.24C, TM 2.4.24.5

• TMA Testing in Extension/Tensile

• This method can test the properties of films and fibers under a static load held to obtain a CTE on delicate materials. In addition, a creep-recovery or stress relaxation test can also be performed in order to determine material failure and change under variable loads.

• Applicable Methods:

  • ASTM E1824

• Flexural

• Where a sample is balanced on two points and the probe is placed between the two points. Heat Deflection Under Load (HDUL) or simply Heat Deflection Temperature (HDT) can be simulated with this method. This is also called Three-Point Bending.

• Applicable Methods:

  • ASTM E2092

• Penetration Testing

• Also known as indentation testing.

• Vicat Softening Temperature: This can be simulated by TMA by the use of a small flat tipped probe to yield the softening point

• Applicable Methods:

  • ASTM E2347

  • ISO 11359

• Compression

• This can be used to determine the softening temperature of resins and other materials, as well as to determine the glass transition temperature (Tg) and melting point.

• Applicable Methods:

  • IPC-TM-650: TM 2.4.24C, TM 2.4.24.3, TM 2.4.24.5

  • ASTM E1545

• Dilatometric Testing

• Dilatometry can measure the shrinkage or expansion of materials that are not solid enough to be run alone in the TMA or where volumetric expansion is required. The use of a dilatometer can be useful for gels, glues, epoxies, and many other soft or liquid materials.

• Other Static Load Tests

• TMA instruments offer the option of limited stress-strain, creep-recovery, and stress-relaxation methods.

• Delamination

• A key factor in the development of electronics and printed circuit boards (PCB); this can determine if the board is suitable for development and production. There are several ways that delamination can occur, such as moisture in the board, thermal shocks, lamination errors, or even using materials with an unsuitable glass transition (Tg). This can lead to the scrapping of boards and wasted product. This test is normally preformed in a TMA.

• Applicable Methods:

  • IPC-TM-650: TM 2.4.24.1

CTE and Tg of an Epoxy Resin by TMA