Castings Glossary Alloy — A substance containing two or more chemical elements, at least one of which is metal.Castings Glossary Alloy — A substance containing two or more chemical elements, at least one of which is metal.Castings Glossary Alloy — A substance containing two or more chemical elements, at least one of which is metal.Castings Glossary Alloy — A substance containing two or more chemical elements, at least one of which is metal.Castings Glossary Alloy — A substance containing two or more chemical elements, at least one of which is metal.