INFLUENCE OF Ti MICROALLOYING ON ZAMAK-5

ZAMAK-5 is a Zn-Al alloy which contains 3.9-4.3 % Al, 0.75-1.25 % Cu and 0.03-0.06 % Mg. Low melting temperature and good castability are some of the advantages of ZAMAK-5. In the present study, the composition of ZAMAK-5 alloy was modified by microalloying it with Ti. Alloying was accomplished by melting ZAMAK-5 at 450 and 650 oC and introducing Ti as Al10Ti master alloy. It was found by ICP analyses that modified alloys contained 0.01 and 0.03 wt.% Ti. Re-melting and casting of the alloyed samples were conducted at 650 oC under argon atmosphere. The modified alloy that contained 0.03 % Ti had near eutectic Zn-Al composition due to the increased amount of Al. The increase in the Al content was caused by master alloy addition. According to microstructural and solidification analyses, the modified alloy that contained 0.03 % Ti had lower liquidus temperature and less primary (η) dendrites in its microstructure. Alloying with Ti was found to increase hardness and bending strength of the base alloy. Alloy that was modified with 0.03 % Ti exhibited the highest hardness (102.3±2.8 HB10), compressive yield strength (290.0±5.0 MPa) and bending strength (661.4±30.5 MPa).