1. Take TEM images
2. Using ImageJ first set the scale bar
3. Measure the length of precipitates using line measurement in ImageJ
4. Assume sample thickness is of the order of 70 nm
5. Correct the measured precipitate size using equation (1)

Example: Plate-like T1 (Al2CuLi) precipitate in Al-Cu-Li alloys as shown in figure 1.

Figure 1: (a) Plate-like T1 precipitate in Al-Cu-Li alloy. (b) Precipitates which were used to calculate the diameter of plate-like precipitates .

Table 1: Measured diameter of the marked red colour precipitates.