Table 3 Summary of the residual stress after 3 h stress relaxation

room temperature

initial stress(MPa)

11.94 ± 0.74

12.72 ± 0.52

12.88 ± 1.28

11.33 ± 0.43

5.07 ± 2.08

residual stress(MPa)

10.54 ± 0.48

11.08 ± 0.43

11.7 ± 0.75

10.08 ± 0.73

3.17 ± 1.22

normalized residual stress(%)

88.31 ± 0.22

87.11 ± 0.17

90.81 ± 0.20

88.97 ± 0.42

62.55 ± 0.79

decreasing rate(%)

11.69

12.89

9.19

11.03

37.45

37 °C

initial stress(MPa)

12.52 ± 0.43

11.55 ± 0.23

13.41 ± 0.56

11.55 ± 0.23

4.18 ± 0.76

residual stress(MPa)

10.97 ± 0.66

9.19 ± 0.20

11.22 ± 0.38

9.52 ± 0.35

1.86 ± 0.99

normalized residual stress(%)

87.56 ± 0.32

79.62 ± 0.47

83.58 ± 0.28

82.40 ± 0.31

44.44 ± 0.30

decreasing rate(%)

12.39

20.38

16.32

17.6

55.56

55 °C

initial stress(MPa)

12.36 ± 0.63

12.49 ± 0.55

11.36 ± 1.23

10.71 ± 0.82

2.71 ± 1.76

residual stress(MPa)

0

0

5.64 ± 0.75

2.2 ± 0.33

1.14 ± 0.82

normalized residual stress(%)

0

0

49.61 ± 0.12

20.5 ± 0.61

42.01 ± 0.35

decreasing rate(%)

100

100

50.39

79.5

57.99