不良・失敗
thermal shock
Japanese: 熱衝撃
A phenomenon in which sudden heating or cooling creates a temperature difference between the surface and the center, and the resulting difference in expansion generates tensile stress that causes cracking. / Note: This is more likely to occur in thicker materials. The main cause is exceeding the speed limit in the solid state.
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Thermal shock is a phenomenon in which rapid heating or cooling creates a temperature difference between the surface and the core, and the resulting difference in thermal expansion generates tensile stress that causes cracking. Stress is expressed as σ = αEΔT/(1−ν); for the COE90 series, it reaches approximately 80 MPa at a temperature difference of 100°C between the interior and exterior, easily exceeding the practical strength limit.
The main cause is rapid heating and cooling in the solid region (below the strain point). The thicker the material, the more likely this phenomenon is to occur.
This entry is written in Japanese by Rei Chikaoka and translated for readers outside Japan. If something reads oddly, the original is the source of truth.