Currently, I'm studying about Ultrasound wave. My aim is set up a system that ultrasound wave can go through ( not reflect and not absorb ultrasound wave). Besides that, this material can contain liquid. Can you give me what materials can adapt this experiment? Best regards.
Since ultrasound is often used for medical purposes on humans and animals, I would think that ballistic gelatin could be used for this experiment. It supposedly has the same density as muscle tissue, and is comprised primarily of water, much the same as muscle tissue. The best part is, you can set objects (fake skeletal structure or other foreign objects) into the mold before pouring in the mixture!
Here is a link to an instructable on how to make regulation test grade ballistics gel:
Any common lab materials will do if all you need is for the ultrasound waves to pass through them, like glass or aluminum plate. More importantly is that the material must not porous and have a good surface condition. Also the angle of incident should be perpendicular to the material surface. Look at the table on the bottom of this page:
Real value should varies based on surface treatment etc, but it's good for comparison of which one is better than the others. I would suggest aluminum or glass.
If you really need a material with as low attenuation as possible for your project, however, you might want to use single crystal metals. The grain boundaries in polycrystalline materials causes scattering in sound wave and increase attenuation, single crystal material has no grain boundaries, it will perform better. Casting a large size single crystal metal alloys is possible , they do so with nickel alloy for turbine blades since long ago. However I'm sure it will be very expensive.