ISO 21618:2019 pdf free download – Fine ceramics (advanced ceramics, advanced technical ceramics )一 Test method for fracture resistance of monolithic ceramics at room temperature by indentation fracture (IF) method.
7.8 Measurement of indentation size
7.8.1 Measure both diagonals of each hardness impression as “2a” values to within 1 p.m within 10 mm of unloading. The measurement procedure described in ISO 14705 or the following apply.
7.8.2 Adjust the diagonal directions to both vertical and horizontal axes of the field of optics.
7.8.3 Centre the left corner of the diagonal in the field of optics and record the stage position.
7.8.4 Shift the stage to centre the right corner of the diagonal in the field of optics and record the stage position.
7.8.5 Calculate the horizontal diagonal size, 2ai, from the change of stage position.
7.8.6 Obtain the vertical diagonal size, 2a2, following the same procedure as 7.8.3 to 7.8.5.
7.9 Measurement of crack size
7.9.1 Measure both horizontal and vertical crack length as “2c” values to within 1 p.m within 10 mm of unloading. The following measurement procedure shall be used.
7.9.2 Centre the left crack tip in the field of optics as shown in Figure 4 (left) and record the stage position. To identify the crack-tip position, it is recommended that the image is brought into focus and out of focus several times by turning the fine knob back and forward quickly.
7.9.3 Shift the stage to centre the right crack tip in the field of optics as shown in Figure 4 (right) and record the stage position.
7.9.4 Calculate the horizontal crack length, 2ci, from the change of stage position.
The test report shall be prepared in accordance with ISO/IEC 17025, unless there are valid reasons for not doing so. The report of the results of an indentation fracture resistance test shall include the following items:
a) the name and address of the testing establishment;
b) the date of the test, a unique identification of the report and of each page, customer name and address and signatory of the report;
c) a reference to this document, i.e. determined in accordance with Iso 21618;
d) a description of the test material, elastic modulus, batch codes and date of manufacture, as appropriate;
e) geometry and dimensions of the test specimen;
f) sampling conditions of the test specimen from material and its machining conditions (when a specimen is heat treated, its conditions are included);
g) name and type of testing machine;
h) name and type of microscope;
i) magnification of objective lens and total magnification used to observe and measure the cracks;
j) environment of test, relative humidity and temperature;
k) indentation force;
l) elastic modulus used to calculate the indentation fracture resistance as well as the measuring method, i.e. determined with ISO 17561. If literature data were used, the source of the data should be provided;
m) a list of test results (number of valid indentations measured, as well as the total number of indentations, mean indentation fracture resistance and the standard deviation);
n) deviations from the specified procedures, if any.
The report of the results of an indentation fracture resistance test should preferably also include the following items:
o) kinds of additives and sintering method of test material;
p) mechanical properties of test material such as bending strength or Vickers hardness;
q) porosity of test material when slightly porous ceramics are employed.