FINDING THE POROSITY PERECENTAGE FOR SMART ALLOY (Cu-Al-Ni) SAMPLES WHEN CHANGING THE SINTERING TIME AT THE FIRST STAGE

In this research the effect of porosity is studied at three different holding times(1.5, 1 and 0.5 hours) for the first sintering stage, to fixing aluminium in its solid state phase at temperatures (500°C), of the memory alloy based on copper. The powder metallurgy method has been used to manufacture 3 samples for this alloy with(83%Cu,13%Al,4 %Ni). To make sure of the generation phases for Marten site and Austenite, physical tests (Optical microscopy, XRD, and SEM) were carried out before and after sintering. The porosity testing was conducted on these samples, depending on the specification (ASTM B 328). The percentage of porosity is generated at the three holding times for the first stage was calculated, according to the equation adopted that. The results give, the lowest porosity% was at 0.5 hours with a value of 2.907 %, at 1.5 hours was the highest value for porosity 3.733%, at either hour the value of porosity was 3.720%. In this way we observe the effect of the holding time of the first stage of sintering on the porosity. The relationship was a positive, the greater the holding time, it gives a greater percentage of porosity. It gives an indication of the utilization of those in the process of sintering to obtain the required percentage of porosity, especially in products that need it, such as self-lubricating bearings.