If you are asking about reading aloud / pronouncing it in speech, then generally when chemists and other scientists talk about chemical formulae, they would most commonly pronounce the individual letters of the chemical symbols. So in your example, "A-L-three-T-I" (ay-el-three-tee-eye).

For a less common alloy or compound like this, the first time you say it, you might say the full name of the elements ("aluminium three titanium"), but this becomes a bit of a mouthful, and once the audience understands what you're referring to, its easier to spell out the symbols.

Some things are so common they sound a bit odd if you say the full names of the elements. We would always refer to methane (CH4) as "see-H-four", instead of "carbon hydrogen four".

I think these rules would work generally, but there is another more complicated option for your second example. Some compounds have chemical names which are easier to use. Another way to read TiB2 would be titanium diboride, but going into that here would (further?) over complicate my explanation.

Source: I used to be a researcher in chemistry / metallurgy / engineering, and attended a lot of conferences, had discussions, etc., where people had to refer to these formulae!