Engineering Lab Report Sample, Master's Student
Precipitation hardening in 2024 Aluminum
Lab Report
Abstract “Age or Precipitation Hardening” effects on the 2024 Aluminum sample (Al-4%Cu) was investigated by conducting two sets of experiments on 5 samples. In the first experiment, 4 of the samples were artificially aged, and in the second experiment, only one of the 5 samples were naturally aged. In conclusion, it is concluded that the hardness of the samples is directly affected by the time and the temperature of the age hardening, so as the samples are age hardened longer and in a higher temperature, the hardness of them increases accordingly. Description of theory Age or Precipitation hardening is a widely used heat treatment method that is done to raise the strength (including the yield and ultimate tensile strength) of malleable materials such as Aluminum. In precipitation hardening, the formation of a very fine and uniformly distributed second phase particles in the initial phase causes the yield strength of material to increase. These second fine phase in the structure of the materials plays a very important role in the motion of dislocations by impeding their movement with making a defect in the crystal lattice, which both causes the higher yield strength into the material. (Smith)
1
In this experiment all the necessary steps to implement a natural and artificial aging is done as follows (Fig 1): In the first step that is called solution treatment, the alloy (AL-4Cu) is heated up to the alpha region (Fig 1, and Fig 4 Appendix), and soaked there for enough time to get a homogenized solid solution of alpha. Second, the Aluminum sample is quenched into water in order to form a supersaturated solid solution of alpha, containing excess copper. This phase is not considered an equilibrium phase and similar to the martensitic structure in steels that the atoms of carbon doesn’t have enough time to diffuse to the outside of the atomic lattice and form a second phase, the copper inside the lattice
Lab Report
Abstract “Age or Precipitation Hardening” effects on the 2024 Aluminum sample (Al-4%Cu) was investigated by conducting two sets of experiments on 5 samples. In the first experiment, 4 of the samples were artificially aged, and in the second experiment, only one of the 5 samples were naturally aged. In conclusion, it is concluded that the hardness of the samples is directly affected by the time and the temperature of the age hardening, so as the samples are age hardened longer and in a higher temperature, the hardness of them increases accordingly. Description of theory Age or Precipitation hardening is a widely used heat treatment method that is done to raise the strength (including the yield and ultimate tensile strength) of malleable materials such as Aluminum. In precipitation hardening, the formation of a very fine and uniformly distributed second phase particles in the initial phase causes the yield strength of material to increase. These second fine phase in the structure of the materials plays a very important role in the motion of dislocations by impeding their movement with making a defect in the crystal lattice, which both causes the higher yield strength into the material. (Smith)
1
In this experiment all the necessary steps to implement a natural and artificial aging is done as follows (Fig 1): In the first step that is called solution treatment, the alloy (AL-4Cu) is heated up to the alpha region (Fig 1, and Fig 4 Appendix), and soaked there for enough time to get a homogenized solid solution of alpha. Second, the Aluminum sample is quenched into water in order to form a supersaturated solid solution of alpha, containing excess copper. This phase is not considered an equilibrium phase and similar to the martensitic structure in steels that the atoms of carbon doesn’t have enough time to diffuse to the outside of the atomic lattice and form a second phase, the copper inside the lattice
References: Key to Metal Precipitation Hardening of Alominum Alloys. (2010, January). Retrieved from www.keytometal.com Figure 4: Phase Diagram of Al-Cu (Key to Metal Precipitation Hardening of Alominum Alloys, 2010) Component Component Wt Table 5: Aluminum 2024 Chemical Composition (Key to Metal Precipitation Hardening of Alominum Alloys, 2010) 8