Effect of Liquid/Solid Volume Ratio on Interface Formation and Mechanical Properties of Aluminum – Copper Bimetal by Squeeze Casting

Abstract

Many industrial applications require lightweight, low cost and high- performance materials. This work created a bimetal (Al-Cu) using the compound casting technique (Squeeze casting). Nickel-electro coating of copper substrates was used before casting; the copper inserted was a cylindrical rod into a carbon steel die, then melted aluminum at (700˚C). The liquid to-solid ratio influenced the formation of the interface (transition region between the two metals). Also the mechanical characteristics of the bimetal (Al-Cu) were studied. The intermetallic compounds were discovered as (Al_2 Cu,AlCu_4,AlCu,Al_4 Cu_(9,) and Cu_4 Al_3). The nickel coating significantly enhanced and strengthened the bimetal (Al-Cu) interconnection by percentages (17% and 3.5%). Many tests and examinations were conducted, such as examining the microstructure with an optical microscope, scanning electron microscope and X-ray diffraction, hardness and interconnection strength examinations due to restricting the formation of intermetallic compounds. The results also showed that the interface had a thickness and good properties at a ratio of liquid to solids of 17% because the large thermal content increased the interface thickness between the two metals. The effect of this ratio was evident through the tests’ results, as the interconnection strength reached 15.5 MPa. The copper and aluminum interfaces' hardness were is 168, 92, and 38 HV, respectively. While the intermetallic compounds were more diverse at a liquid to- solid ratio of 17%.

Keywords

• Compound casting
• Al-Cu bimetal
• Intermetallic compound
• Interface formation