Traditionally Yield Strength and Ultimate Tensile Strength have been tested using a large tensile testing machine requiring enormous strength to pull apart test specimens. It is costly and time-consuming to properly machine many test coupons for a material where each sample can only be tested once. Small defects in the sample create a noticeable variance in test results. Different configurations and alignments of the tensile testers in the market often result in substantial variations in testing mechanics and outcomes.

Measurement Objective

In this application, the Nanovea Mechanical Tester measures the Yield Strength and Ultimate Tensile Strength of stainless steel SS304 and aluminum Al6061 metal alloy samples. The samples were chosen for their commonly recognized Yield Strength and Ultimate Tensile Strength values showing the reliability of Nanovea’s indentation methods.

Test Procedure and Procedures

The Yield Strength and Ultimate Tensile Strength tests were performed on the Nanovea Mechanical Tester in the Microindentation mode. A cylindrical flat diamond tip of 200 μm diameter was used for this application. SS304 and Al6061 alloys were selected for their extensive industrial application and commonly recognized Yield Strength and Ultimate Tensile Strength values, in order to show the great potential and reliability of the indentation method. Samples were mechanically polished to a mirror-like finish before testing to avoid surface roughness or defect influence on test results. Test conditions are listed in Table 1. More than ten tests were performed on each sample to ensure the repeatability of the test values.

Results and Discussion

Load-displacement curves of the SS304 and Al6061 alloy samples are shown in Figure 3 with the flat indenter imprints on the test samples inset. Analysis of the “S” shaped loading curve using special algorithms developed by Nanovea calculates Yield Strength and Ultimate Tensile Strength . Values are automatically calculated by the software as summarized in Table 1. Yield Strength and Ultimate Tensile Strength values obtained by conventional tensile tests are listed for comparison.

Conclusion

In  this  study,  we  showcased  the  capacity  of  Nanovea  Mechanical  Tester  in  evaluating  Yield Strength & Ultimate Tensile Strength of stainless  steel and aluminum alloy sheet samples. The simple experimental setup significantly cuts the time and cost for  sample  preparation  required  for  tensile  tests.  The  small  indentation  size  makes  it  possible  to  perform  multiple measurements  on  one  single  sample.  This  method  allows  YS/UTS  measurements  on  small  samples  and localized areas, providing a solution for YS/UTS mapping and local defect detection of pipelines or auto structure.

The  Nano,  Micro  or  Macro  modules  of  the  Nanovea  Mechanical  Tester  all  include  ISO  and  ASTM  compliant              indentation,  scratch  and  wear  tester  modes,  providing  the  widest  and  most  user  friendly  range  of  testing  available in a single system. Nanovea’s unmatched range is an ideal solution for determining the full range of mechanical properties of thin or thick, soft or hard coatings, films and substrates, including hardness, Young’s modulus, fracture toughness, adhesion, wear resistance and many others.  In addition, optional 3D non-contact profiler and AFM Module are available for high resolution 3D imaging of indentation, scratch and wear track in addition to other surface measurements such as roughness.