|About this Abstract
||2023 TMS Annual Meeting & Exhibition
||Phase Transformations and Microstructural Evolution
||Evolution of Phase Transformation Texture during Annealing in the Electroformed Invar
||In Gyeong Kim, Jun Ha Lee, Yong Bum Park
|On-Site Speaker (Planned)
||In Gyeong Kim
In the OLED display industry, Invar(Fe-36%Ni) exhibiting anomalous low thermal expansivity is used as a material for the fine metal mask (FMM), which guides the evaporated diode materials through its small holes onto the correct positions of the substrate glass. The electroformed Invar can perform a low coefficient of thermal expansion (CTE) via sophisticated heat treatment where the phase (BCC) and/or γ′ phase (FCC) in the as-deposited state are transformed into the γ″ phase (FCC). This phase transformation gave rise to the texture evolution. The texture developed in as-deposited state depending on the alloy composition was transformed into the as-annealed texture with the major <111>//ND and minor <100>//ND components. This texture evolution that takes place during annealing can be attributed to a combined effect of abnormal grain growth (AGG) accompanied by the γ′ → γ″ phase transition and the α → γ″ (or α → γ'→ γ″) phase transformation.