الفهرس Only 14 pages are availabe for public view
 |  | from | 113 |  |  |
| | | from | 113 | | |
Abstract
The present study is dealing with modification of mechanical properties of Al - Mg - Si alloy 6351 by age hardening. The study investigates the effect of aging temperature, time, natural aging and pre-aging on artificial aging behavior in terms of mechanical properties and fractography examination. Artificial aging after solution treatment-water quenched resulted in a sharp increase in both ultimate tensile strength UTS and yield stress YS, can lead with a decrease in total elongation. As the time of aging increase the strength increase slightly till reaches peak strength after that it starts to decrease with increasing time of aging. Better mechanical properties are observed at lower aging temperature. Natural aging at room temperature (25 ± 3oC) after solution treated - water quenched resulted in a mild increase in tensile properties with a slight DROP in total elongation, natural aging for 170 h and for 1000 h after solution treatment followed by artificial aging of this alloy at 160oC, shifted the time to reach peak strength to shorter aging time (8 - 4 h respectively) in comparison to peak-aged condition (160oC for 18 h). Pre - aging at 100oC for various times before artificially aging at 160oC for 18 h was investigated. It was found that the pre - aging for 10 min followed by artificially peak aging led to slight increase in ultimate tensile strength and yield stress YS associated with a reasonable total elongation