Evaluation of Material Properties in Austenite Stainless Steel Sheet with Scanning Acoustic Microscopy

Abstract

Austenite stainless steel 304 has properties of high resistance to corrosion and temperature changes. Therefore, this material is widely used in various of industries. However, when the material is subjected to heating and cooling cycles the forming accuracy, for example, the right angle associated with a sharp bend such as corner is lost. This phenomenon is caused by the reversion of the deformation-induced martensite into austenite when the temperature in increased. This result in misfit of a structure or an assembly, and an increase in residual stress. Hence, it is important to understand this process.In this study, to evaluate the mechanical behavior of the deformation-induced martensite and reversed austenite, a scanning acoustic spectroscope including the capability of obtaining both phase and amplitude of the ultrasonic wave (i.e., the complex V(z) curve method) was used. Then, the velocities of the SAW propagating within the specimens made in different conditions were measured. The experimental differences of the SAW velocities obtained in this experiment were ranging from 2,750 m/s to 2,850 m/s, and the theoretical difference was 3.6% under the assumption that the SAW velocity was 2,800 m/s. The error became smaller as the martensite content was increased. Therefore, the SAW velocity may be a probe to estimate the marternsite content.

Through-Silicon via Device Non-Destructive Defect Evaluation Using Ultra-High-Resolution Acoustic Microscopy System

“…Thus, a technique that can precisely evaluate the surface, surface layer, and interface characteristics is required. The nondestructive evaluation (NDE) that utilizes ultrasonic waves is the only technique that can evaluate the surface and interface characteristics of thin film structures [ 7 , 8 , 9 , 10 , 11 , 12 ]. With the increased applications of acoustic microscopy, it was not difficult to inspect the inside of the past semiconductors using 15–100 MHz ultrasonic waves because their total thickness exceeded 3 mm and the thickness of the silicon die inside them was more than 1 mm [ 13 , 14 ].…”