# 열처리된 재료의 초음파 비선형성에 관한 연구

• Li, Weibin (School of Mechanical Engineering, Pusan Nat'l Univ.) ;
• Lee, Jae-Sun (School of Mechanical Engineering, Pusan Nat'l Univ.) ;
• Cho, Youn-Ho (School of Mechanical Engineering, Pusan Nat'l Univ.)
• Received : 2010.01.05
• Accepted : 2010.04.01
• Published : 2010.06.01
• 43 4

#### Abstract

Ultrasonic nonlinearity is very sensitive to changes in material properties. This paper describes the study of the correlation between heat treatment and ultrasonic nonlinearity by taking nonlinear factors into consideration. A modified formula was proposed for ultrasonic velocity. This formula indicated that the changes occurring in nonlinearity during heat treatments cause changes in the ultrasonic velocity. The experimental results show that the relative nonlinearity parameters calculated from the modified ultrasonic velocities and the ratio of amplitudes of the second harmonic and fundamental wave are in good agreement. The experimental results prove that heat treatment can result in changes in material nonlinearity. Moreover, the relative nonlinearity parameter calculated from the modified velocity formula is has a large value. Since this parameter has high sensitivity to changes in nonlinearity, it can be used to represent the relative nonlinearity change calculated in this study by using the modified formula for ultrasonic velocity.

#### Keywords

Ultrasonic Nonlinearity;Heat Treatment;Internal Stress;Dislocation

#### Acknowledgement

Supported by : 한국연구재단

#### References

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#### Cited by

1. Experimental Study on Corrosion Detection of Aluminum Alloy Using Lamb Wave Mixing Technique vol.40, pp.11, 2016, https://doi.org/10.3795/KSME-A.2016.40.11.919