ZnAl alloy
Hi /sci/. Do you have experience with metal alloys and die casting? I did some experiments with ZnAl alloy (50/50) which I cast into small tubes. I used a special lubricant for casting and I washed finished product in a special degreasers. After 24hrs I placed the tubes in a furnace at 300*C for 2 hrs. After cooling some of the tubes have bulges (as you can see on the picture). Some of the tubes also have a dark brown stain on them.
There are two hypothesis on the nature of those issues. The firs one is that it is the lubricant occluded in the metal which evaporates and expands when heated causing the bulging. Also the brown stain would suggest that is is the carbonised lubricant, but not all tubes which are stained have bulges.
The second hypothesis is that it is hydrogen. Due to reaction of liquid Al with water vapour hydrogen is created and dissolves in liquid metal. There are bubbles of this gas in the finished product which expand and cause the bulging.
Additional question is: would it be possible for the hydrogen to slowly diffuse through the metal structure into environment?
What is your opinion on this, /sci/?
Hi /sci/. Do you have experience with metal alloys and die casting? I did some experiments with ZnAl alloy (50/50) which I cast into small tubes. I used a special lubricant for casting and I washed finished product in a special degreasers. After 24hrs I placed the tubes in a furnace at 300*C for 2 hrs. After cooling some of the tubes have bulges (as you can see on the picture). Some of the tubes also have a dark brown stain on them.
There are two hypothesis on the nature of those issues. The firs one is that it is the lubricant occluded in the metal which evaporates and expands when heated causing the bulging. Also the brown stain would suggest that is is the carbonised lubricant, but not all tubes which are stained have bulges.
The second hypothesis is that it is hydrogen. Due to reaction of liquid Al with water vapour hydrogen is created and dissolves in liquid metal. There are bubbles of this gas in the finished product which expand and cause the bulging.
Additional question is: would it be possible for the hydrogen to slowly diffuse through the metal structure into environment?
What is your opinion on this, /sci/?
