In which alloy, aluminium is not present?

Options

A. Duralumin
B. Brass
C. Alcino
D. Magnalium

Answer

To determine which alloy does not contain aluminum, we will analyze each option provided in the question:

1. **Duralumin**:
- Duralumin is an alloy primarily composed of aluminum (90-94%), along with copper (4%), and small amounts of manganese and magnesium.
- **Conclusion**: Duralumin contains aluminum.

2. **Brass**:
- Brass is an alloy made primarily of copper and zinc. It does not contain aluminum as one of its main components.
- **Conclusion**: Brass does not contain aluminum.

3. **Alnico**:
- Alnico is an alloy that includes aluminum, nickel, and cobalt. The name itself indicates the presence of aluminum.
- **Conclusion**: Alnico contains aluminum.

4. **Magnelium**:
- Magnelium is an alloy consisting of magnesium and aluminum, with aluminum being the major component (approximately 95%).
- **Conclusion**: Magnelium contains aluminum.

After analyzing all the options, we find that the alloy in which aluminum is not present is **Brass**.

### Final Answer:
**Brass**