Thin films with precisely engineered nanostructures

TL;DR

This paper introduces a novel in-situ seeding method for synthesizing nanostructured thin films with precise control over grain size, distribution, and geometry, enhancing their mechanical properties for various applications.

Contribution

The authors develop a new methodology for microstructural control in thin films through systematic nanocrystal seeding and thermal annealing, applicable to multiple alloy systems.

Findings

Achieved precise control over nanograin size and distribution.

Demonstrated applicability to TiAl and TiNi thin films.

Enabled tailored microstructures for improved properties.

Abstract

Synthesis of rationally designed nanostructured materials with optimized mechanical properties, e.g., high strength with considerable ductility, requires rigorous control of diverse microstructural parameters including the mean size, size dispersion and spatial distribution of grains. However, currently available synthesis techniques can seldom satisfy these requirements. Here, we report a new methodology to synthesize thin films with unprecedented microstructural control via systematic, in-situ seeding of nanocrystals into amorphous precursor films. When the amorphous films are subsequently crystallized by thermal annealing, the nanocrystals serve as preferential grain nucleation sites and control their microstructure. We demonstrate the capability of this approach by precisely tailoring the size, geometry and spatial distribution of nanostructured grains in structural (TiAl) as well as functional (TiNi) thin films. The approach, which is applicable to a broad class of metallic alloys and ceramics, enables explicit microstructural control of thin film materials for a wide spectrum of applications.