Author : Abdalwahid K. Rajih, Dhafer S. Al-Fattal and Salah N. Alnomani

It is well established that smart alloys prepared by powder metallurgy (P.M) techniques need to be sintered at elevated temperatures. There is Evidence that the sintering process of (Cu-Zn-Al) alloys is associated with a significant loss of zinc and the alloy may no longer behaves as a shape memory alloy. For instance, usual sintering processes if start at about 20.8%wt Zn will end up with almost 0.67%wt Zn. However, the new method ends with 20.48wt% Zn. An alternative method is available but, unfortunately, it is costly. Factors responsible for zinc evaporation are hopefully eliminated during this work. A container is specially designed and fabricated from quartz and the samples are protected by this sealed container during sintering. A pressurized argon inert gas is injected into the container before sealing. Hot isostatic pressure is also used in this research which plays an important role in this respect. An outstanding result has been obtained; there is almost no loss in zinc content after sintering. In addition to the above mentioned advantages, there is a substantial reduction in soaking time at such high temperatures.

Keywords: Powder metallurgy, Sintering, Shape memory alloys, Porosity, Zinc evaporation.

Article published in International Journal of Current  Engineering  and Technology, Vol.4,No.3 (June- 2014)