Table 1.

Different stress amplitudes used to construct S-N curves for different stress ratios (R).

Load regime	R	σa,1	σa,2	σa,3	σa,4	σa,5	σa,6
		MPa	MPa	MPa	MPa	MPa	MPa
Compression-compression	10	9	11.25	13.5	18	22.5
Tension-tension	0.1	6.75	9	11.25	13.5	15.75	18
Tension-compression	−1	7	10	15	20	25