Magnesium and its alloys

Magnesium and its alloys

1. Magnesium and its alloys V.Himasree(MM17B113) P.Sree Keerthi(MM17B023) Arya Nilesh Ukunde(MM17B012)

2. CONTENT: 1.Introduction 2.Characterisation of base metal 3.Alloying elements 4.Alloying effects 5.Alloys Nomenclature 6.Types of alloys 7.References

3. Great chemical stability Ease of machinability and fabrication Light weight Environmentally friendly 2/3rd the weight of aluminium alloys and 1/3rd the weight of iron and steel. Used for structural applications primarily in aircraft and missile industries. High thermal conductivity,tensile strength(228-290 MPa),heat resistance(upto 450 deg),oxidation resistance(upto 500 deg). INTRODUCTION

4. 8th most abundant metal. 2% of earth’s crust Cheapest and lightest metal. 3rd most plentiful element dissolved in seawater. Found in over 60 minerals,among them dolomite,magnesite,brucite,carnallite & olivine are commercially important. It forms alloys but use has been limited by its tendency to corrode, creep at high temperatures and combust. CHARACTERISATION OF BASE METAL (Mg)

5. Aluminium Manganese Zinc Zirconium Thorium Tin Beryllium Calcium Cerium Copper ALLOYING ELEMENTS

6. Addition of aluminium increases hardness and strength,reduces ductility If Al % is greater than 13,the material becomes too brittle. Addition of Mn increases corrosion resistance. To improve corrosion resistance under saline conditions 1-2%Zn is added. Zirconium r efines grain size in sand and gravity castings (not combined with aluminum) Tin improves castability. Aluminium,zinc,zirconium and thorium promote precipitation hardening. Copper increases both room and high temperature strength. ALLOYING EFFECTS

7. NOMENCLATURE The most common designation of magnesium alloys is based on ASTM publication. The first two letters of ASTM nomenclature indicate principal alloying elements. A-aluminium;B-bismuth;C-copper;D- cadmium,E-rare earths;F-iron;G-magnesium,H-thorium;K-zirconium;L-lithium;M-manganese;N-nickel;P-lead;Q-silver;R-chromium,S-silicon,T-tin,Y-antimony,Z-zinc The two alloying elements are arranged in order of decreasing percentage,or in alphabetical order if of equal percentages followed by respective percentages rounded off to whole numbers.

8. Example:

9. AZ91E-T6

10. Magnesium, Aluminium and Zinc Common type of heat treatable alloy Artificial or natural aging causes increase in yield strength Ductility of the alloy decreases due to heat treatment Lightweight and highly corrosion resistant It is manufactured in various ratios E.g.-High Mg(e.g.-93%Mg 6%Al%1Zn-AZ61A), similarly high Al, high Zn

11. Small amounts of Zirconium, manganese and chromium may be added to obtain fine grain structure before heat treatment. Corrosion resistance is good in the alloys containing small amount of copper. Used in various aircraft structures Forging, extrusions, sheets. Manufacturing hydraulic equipments

12. Magnesium, Zinc, Rare earth(Re) and Zirconium Alloys Most widely used alloys for sand casting Rare earth is added to improve castability Complex castings can be made with virtually no microporosity Retains mechanical properties upto temperature of 150℃ Used in gear box casting, jet engines, etc.

13. Magnesium, Zirconium Alloys containing Silver Improved high temperature (200℃) properties compared to Mg-Zn- Rare earth-Zr alloy Silver is the main strengthening element Common alloy contains 2.5% SILVER Rare earth elements added - neodymium, praseodymium Uses - Aerospace gearbox, engine casings requiring high temperature performance.

14. Magnesium, Zirconium Alloys containing Yitrium Improved mechanical properties at high temperature compared to other magnesium alloys Considered as alternative to thorium containing alloys Very high resistance to corrosion than other magnesium alloys Uses - Alternative to Al alloys in racing cars for large engine casting Many applications in aerospace industry due to its combination of strength ductility and corrosion resistance.

15. ELEKTRON ( ELEKTRONMETALL ) One of the most famous alloys of Magnesium. British company Magnesium Elektron Ltd. 0% to 9.5% alloying elements. Composition: Aluminium(<9.5%), Yttrium(5.25%), Neodymium(2.7%), Silver(2.5%), Gadolinium(1.3%), Zinc(0.9%), Zirconium(0.6%), Manganese(0.5%) and other rare earth elements Varying composition - variations in properties.

16. E LEKTRON ( ELEKTRONMETALL ) One of the most famous alloys of Magnesium. British company Magnesium Elektron Ltd. 0% to 9.5% alloying elements. Composition: Aluminium(<9.5%), Yttrium(5.25%), Neodymium(2.7%), Silver(2.5%), Gadolinium(1.3%), Zinc(0.9%), Zirconium(0.6%), Manganese(0.5%) and other rare earth elements Varying composition - variations in properties.

17. Unusually light(Specific gravity of about 1.8). Good castability because of low oxidation properties. Due to relatively low density of Magnesium, these alloy variants have different aircraft and motor racing applications.

18. MAGNOX Mainly composed of Magnesium and small amounts of Aluminium. Abbreviation for Mag nesium n on- ox idising. It has many industrial applications.

19. Magnox is used in cladding unenriched Uranium metal fuel to contain fission products in nuclear reactors. Low neutron capture cross section. Limits the maximum temperature of the plant to 360 C. Reacts with water, preventing the long term storage of fuel.

20. MAG-THOR Common name for range of Magnesium alloys containing Thorium. Also contains Manganese and Zinc. Names are given by two letters followed by two numbers. e.g.,HM31 - 3% Thorium and 1% Manganese Light weight High strength High creep resistance(upto 350 C)

21. Low melting point. Rapid oxidation. Several aerospace applications. Was used in engine construction of missiles and drones. (e.g.,Bomarc missile) But, no longer used due to radioactivity of Thorium.

22. Metal 12 Alloy of magnesium and aluminium Developed by samsung in 2018 Lightweight and durable Magnesium is lighter than aluminium and stronger per unit volume at the same time Thus magnesium is also termed as metal of the future

23. Physical metallurgy,vijendra singh. https://www.intlmag.org/page/design_mag_all_ima/Magnesium-Alloys-Overview.htm https://www.asminternational.org/documents/10192/22833166/05920G_SampleChapter.pdf/d1a641ad-e4e8-789d-c565-c9c690c1931e https://www.azom.com/article.aspx?ArticleID=2602 References:

24. THANK YOU!!