Precipitation processes in Al–Mg–Si extending down to initial clustering revealed by the complementary techniques of positron lifetime spectroscopy and dilatometry

• DOI: 10.1007/s10853-018-2612-x
• Publication Date: 2018-06-26T09:46:46Z
• Authors: L. Resch; G. Klinser; E. Hengge; R. Enzinger; M. Luckabauer; W. Sprengel; R. Würschum
• Keywords: Positron Lifetime Spectroscopy; Precipitation hardening; Positron annihilation spectroscopy

The design of specific material properties aluminum alloys demands for a detailed understanding clustering and precipitation processes occurring during heat treatments. Positron lifetime spectroscopy in combination with high-precision dilatometry measurements were taken, allowing comprehensive analysis the aging mechanisms on different timescales temperature regimes, artificial aging. From results, unambiguous experimental evidence following three main steps process is obtained. In first seconds aging, competitive dissolution growth cluster types occurs. Subsequently, clusters start to transform into coherent precipitates, which are mainly responsible hardening effect. For prolonged number density precipitates increases, while positron already reveals simultaneous formation less precipitates.