title: Laser ablation condensation, coalescence, and phase change of dense gamma-Al(2)O(3) particles.
abstract: Dense gamma-Al(2)O(3)condensates, with residual stress up to 3 GPa and ranging from nanometer to an unexpected micrometer size, were formed by pulsed laser ablation on Al target under oxygen background gas for a very rapid heating and cooling effect. Analytical electron microscopic observations indicated such nanoparticles tended to coalesce over {111} facets to form multiple twin and tilt boundary. The micrometer-size particles changed, upon electron irradiation, into metastable orthorhombic delta form full of twin variants and faults parallel to {100}.
authors.affiliation: Institute of Materials Science and Engineering, National Sun Yat-sen University, Kaohsiung, Taiwan, Republic of China.
authors.forename: Chiennan
authors.initials: C
authors.lastname: Pan
authors.forename: Shuei-Yuan
authors.initials: SY
authors.lastname: Chen
authors.forename: Pouyan
authors.initials: P
authors.lastname: Shen