Let's review the concepts of pure substance, heterogeneous mixture, and homogeneous mixture:
A substance is matter that has a uniform and definite composition. All samples of substances, sometimes called pure substances, have identical properties.
A heterogeneous mixture is a mixture in which the composition is not uniform throughout the mixture. You can see various phases. For example, a fruit salad is a heterogeneous mixture.
A homogeneous mixture is a mixture in which the composition is uniform throughout the mixture. For example, salt dissolved in water is a homogeneous mixture.
In this case, based on the definitions, titanium ingot is a pure substance because titanium is an element and its composition doesn't change. A titanium ingot doesn't represent a type of mixture.
