Failure analysis equipment:
In the tensile test, the sample will be made into a standardized shape: two shoulders and a gauge section between. As the load applied on the each ends of the sample, the stress- strain curve will be recorded until the sample reaches its’ ultimate strength.
Hardness test:
There are varieties of hardness tests:
Vickers hardness test:
The Vickers hardness test use a pyramidal diamond indenter to indent the surface of the sample, and the area of indentation will be calculated under microscope. The hardness of the material is shown as the stress of the load on the indenter over the area of indentation.
Brinell hardness test:
The Brinell hardness test uses steel ball or tungsten carbide ball as the indenter. Similar with the Vickes hardness test, the hardness of the material can be calculated by the stress of the load on the indenter over the area of indentation.
Rockwell hardness test:
The Rockwell hardness test will apply a minor load on the surface of the sample and set as zero position. Then the major load is applied and removed.by measuring the depth of penetration of an indenter under the main load from the dial, the hardness can be inferred as the harder material is the less penetration it has.
Knoop hardness test:
In the Knoop hardness test, a pyramidal diamond point is applied to the surface of the sample with a known load. Similar with the Vickers hardness test, the hardness of the material is shown as the stress of the load on the indenter over the area of indentation. This test is specialized for the brittle materials or thin sheets.
- NDT
method:
- Ultrasonic crack detector: the ultrasonic crack
detector uses high frequency acoustic energy to identify the flaws in surface
and subsurface, as the ultrasonic waves travel in the sample material, the wave
will echo from the defects in material.
Phrase array ultra sonic
Newly developed ultrasonic device takes advantage of phased array technology. It uses multiply ultrasonic array to emit and receive ultrasonic in different phase. - Radiographic Testing: by using x-ray orγ-ray
penetrating the sample material, the different composition like difference in
density and thickness will be recorded by the photosensitive screen. Due to the
absorption by variation in composition, the picture of flaw can be analyzed by
the recording screen
- Magnetic particle Testing: the sample will be magnetized,
and then the ferrous iron particles will be applied to the surface. Due to the discontinuous
magnetized surface will allow magnetic flux to leak; such area will attract
particles and showing the defect zone.
- Penetrant Testing: the surface of sample will be
cleaned, then the low surface tension fluid will be applied to the surface and
the excess penetrant is removed from the surface. As the cracks can be colored
by the penetrant, the cracks can be identified.
- Eddy current Testing: the sample will be in a
conductive coil with alternating electrical current. A magnetic field will be
generated by the AC in the coil and the Eddy current in the sample will be induced.
The cracks or flaws will result in a change in Eddy current. By analysis the
result of Eddy current, the internal flaws can be identified.
- Optical
emission scope
By using discharge plasma, the atoms on the surface of sample are vaporized and excited. Excited ions will create a unique emission spectrum by different elements. By diffracting the emission spectrum, the elemental distribution of sample can be identified. - Combustion
Infrared Detection of Sulphur and Carbon
- X-ray
fluorescence (XRF)
While bombarding the material with high-energy X-rays or gamma rays, the fluorescent (secondary emission) X-rays is excited and collected by detector. By analyzing the wavelength distribution or energy distribution, the element of material can be identified. - Scanning
electron microscope
By using a focused beam of electrons, a picture of the surface of sample can be created by collecting the secondary electrons. The resolution of the picture can be as high as less than 1 nm in size. - Energy-dispersive
X-ray spectroscopy (EDS, EDX, or XEDS)
The energy-dispersive X-ray spectroscopy uses the secondary emission of atoms under high-energy beam. An energy-dispersive spectrometer will collect the X–ray of atoms. By analyzing the number and energy of the X-rays, the elemental distribution of sample can be revealed. - Stereo
microscope
The stereo microscope is usually in low magnification (50x). The stereo microscope takes the advantage of two separate optical paths and creates a stereo image for the user. By using stereo microscope, the samples with complex surface can be examed. - Mechanical
test:
In the tensile test, the sample will be made into a standardized shape: two shoulders and a gauge section between. As the load applied on the each ends of the sample, the stress- strain curve will be recorded until the sample reaches its’ ultimate strength.
Hardness test:
There are varieties of hardness tests:
Vickers hardness test:
The Vickers hardness test use a pyramidal diamond indenter to indent the surface of the sample, and the area of indentation will be calculated under microscope. The hardness of the material is shown as the stress of the load on the indenter over the area of indentation.
Brinell hardness test:
The Brinell hardness test uses steel ball or tungsten carbide ball as the indenter. Similar with the Vickes hardness test, the hardness of the material can be calculated by the stress of the load on the indenter over the area of indentation.
Rockwell hardness test:
The Rockwell hardness test will apply a minor load on the surface of the sample and set as zero position. Then the major load is applied and removed.by measuring the depth of penetration of an indenter under the main load from the dial, the hardness can be inferred as the harder material is the less penetration it has.
Knoop hardness test:
In the Knoop hardness test, a pyramidal diamond point is applied to the surface of the sample with a known load. Similar with the Vickers hardness test, the hardness of the material is shown as the stress of the load on the indenter over the area of indentation. This test is specialized for the brittle materials or thin sheets.
- Charpy
impact test:
Also known as Charpy V-notch test, the Charpy test uses a pendulum to impact the sample that is prepared into a notched shape. The energy of fracture can be inferred by the difference in height of hammer before and after impact. - Compression
test
The test uses a universal testing machine to compress on the end of the sample. As the load increased, the stress-strain curve will be recorded. - Bending
test
There are two ways to test bending: three points bending and four points bending test. The sample will be set up on two support pins. The force will apply to the upper surface of sample with one point or two points. - Shear
test
The sample is fixed in the V-notched test machine. A force is applied to each side of the sample in a rail. As the load on the end of the sample increases, the stress- strain will be recorded by the gauge attached 45 degree of the longitudinal of the rail. - Cyclic
load test
The sample will undergo a cyclic stress on the end of surface. The load and the stress rate is setup and the strain will be recorded with the test time. - Hydrostatic
test
- FEM