Which factor is most associated with adjusting the test frequency when inspecting coarse-grained alloys?

Which factor is most associated with adjusting the test frequency when inspecting coarse-grained alloys?

• A. Acoustic noise levels
• B. Scattering of sound
• C. Elastic modulus
• D. Attenuation

Answer: (B)

When ultrasound travels through coarse-grained alloys, the grains scatter the wave. This scattering becomes stronger as the frequency increases, so higher frequencies give better resolution but poorer penetration and more signal loss in these materials. That makes scattering the key factor driving how you set the test frequency: you balance the need for resolution against the loss of signal due to grain scattering, often lowering the frequency to improve penetration in coarse-grained metals. Acoustic noise is external and not what you adjust the frequency for; the elastic modulus mainly affects wave speed, not the primary reason for choosing frequency here; attenuation is related to scattering and absorption but the dominant influence in this context is how much the grains scatter the sound.

When ultrasound travels through coarse-grained alloys, the grains scatter the wave. This scattering becomes stronger as the frequency increases, so higher frequencies give better resolution but poorer penetration and more signal loss in these materials. That makes scattering the key factor driving how you set the test frequency: you balance the need for resolution against the loss of signal due to grain scattering, often lowering the frequency to improve penetration in coarse-grained metals. Acoustic noise is external and not what you adjust the frequency for; the elastic modulus mainly affects wave speed, not the primary reason for choosing frequency here; attenuation is related to scattering and absorption but the dominant influence in this context is how much the grains scatter the sound.