I don't know why either.  Does anyone know the answer to this question?

In many academic institutions around the world, along the recent development in materials science field, those  institutions have changed the name of their "Department of Materials and Metallurgical Engineering" to "Department of Materials Science".   This probably has to do with the "Department of Materials and Metallurgical Engineering" is more related to the old processes of materials & metallurgical engineering in a comparison with "Department of Materials Science", which has to do with the current advancementt of Metallic alloys/Polymers/Ceramics or composites of the Metallic alloys/Polymers/Ceramics.   

Materials Science is a very broad field that cut across Physics and Chemistry as the foundation. Hence, the concept of Materials can't be ignored in any Engineering endeavour. Applications of materials in all areas of Engineering overlap. Using "Materials Science" is believed to be too wide while "Materials Science and Engineering" is narrower. 

Materials and Metallurgical Engineering defines the main focus of their curriculum while addressing other materials to large extent. Polymer Engineering/Science, Metallurgical Engineering, and Ceramics Materials, all define their main areas of interests. In contrast, I have never seen a department named as Composites because of the broader scope it entails.

Hence, names of department in academic should define your strength rather than changing them to Materials Science and/or Engineering. Materials have advanced over the last view decades. Departmental names should assist prospective students save time and resources economic reasons. 

Dear Jaleel

What you have said, it couldn't been said better.

Materials science & engineering will mostly we can see in universities where materials science department is associated with chemical engineering or biotech. In those schools there wont be any much research or academics conducting on the metallurgy part

It is very essential to have the Department of Materials Science and Engineering or Materials and Metallurgical Engineering in any Faculty of Engineering and Technology to actual show the importance of Materials evolution and Development to the technological advancement in this generation. Materials Development is the backbone of Technological advancement so I find it very difficult why the name of the Department is missing in many Universities as at today.

Hi

Engineering schools/colleges around the world have been dominated by how much money /capital that can they obtain/raise in order to have diverse engineering departments like  the Department of Materials and Metallurgical Engineering.