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Effect of Precipitation Hardening Temperatures and Times on Microstructure;Hardness and Tensile Properties of Cast Aluminium Alloy A319 |
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| รหัสดีโอไอ | |
| Creator | 1. Pattama Apichai 2. Julathep Kajornchaiyakul 3. John Thomas Harry Pearce 4. Amporn Wiengmoon |
| Title | Effect of Precipitation Hardening Temperatures and Times on Microstructure;Hardness and Tensile Properties of Cast Aluminium Alloy A319 |
| Publisher | คณะวิศวกรรมศาสตร์ มหาวิทยาลัยนเรศวร |
| Publication Year | 2554 |
| Journal Title | NARESUAN UNIVERSITY ENGINEERING JOURNAL |
| Journal Vol. | 6 |
| Journal No. | 1 |
| Page no. | 28-33 |
| Keyword | Cast aluminium alloy A319,Solution treatment,Aging,Microstructure,Hardness |
| ISSN | 1905-615x |
| Abstract | In the present work;the effect of T6 precipitation hardening on microstructure;hardness and ultimate tensile strength of 5 wt%Si-3.5 wt%Cu-Al (A319) alloy was studied. As-cast A319 samples were solution treated at 503?C for 2-24 hours followed by aging at 150;170;200;230?C for 1-48 hours. Microstructures were studied by OM and SEM-EDS. The phases present were determined by XRD. In the as-cast condition;the microstructure consists of a primary dendritic ?-Al;acicular-plate or globular forms of Si eutectic and intermetallic phases comprising globular Al2Cu and plate-like Al5FeSi in the interdendritic regions. The microstructures after solution treatment and aging are similar to that of the as-cast condition;except that some spheroidisation of the eutectic Si has occurred. After solution treatment at 503?C for 8 hours plus aging at 170?C for 1;6;12;24;36 and 48 hours;the area fractions were decreased to about 11.25 %;10.35 %;9.70 %;9.50 %;9.90 % and 9.85 %;respectively. The precipitation hardening treatment increased the macro-hardness;microhardness;ultimate tensile strength and 0.2 %proof stress compared to the as-cast condition. Peak hardness and maximum levels of tensile strength were obtained after solution treatment at 503?C for 8 hours plus aging at 170?C for 24 hours. At lower aging temperatures or shorter times;the hardness and tensile strength were decreased due to incomplete precipitation. However;at higher aging temperature or longer time;the hardness and tensile strength were decreased most probably due to precipitate coarsening and associated loss in coherency effects |
