A Study on High Strength, High Plasticity, Non-Heat Treated Die-Cast Aluminum Alloy

Abstract

The non-heat-treated, die-cast aluminum alloy samples were prepared meticulously via die-casting technology. The crystal structure, microstructure, and phase composition of the samples were comprehensively studied through electron backscatter diffraction (EBSD), metallographic microscopy, spectrometer, and transmission electron microscopy (TEM). The microhardness and tensile properties of the samples were tested. The die-cast samples were found to have desirable properties by studying the structure and performance of the samples. There were no defects, such as pores, cold partitions, or surface cracks, found. The metallographic structure of the samples was mainly α-Al, and various phases were distributed at the grain boundaries. Before heat treating, α-Al grains were mainly equiaxed with a great number of second phase particles at the grain boundaries. After heat treating, the α-Al grains were massive and coarsened, and the second phase grains were refined and uniformly distributed, compared with those before the heat treating. The EBSD results showed that the grain boundary Si particles were solid solution decomposed after heat treatment. The particles became smaller, and their distribution was more uniform. Transmission electron microscopy found that there were nano-scale Al-Mn, Al-Cu, and Cu phases dispersed in the samples. The average microhardness of the samples before heat treating was 114 HV0.1, while, after the heat treating, the microhardness reached 121 HV0.1. The mechanical features of the samples were tremendous, and the obtained die-cast aluminum alloy had non-heat-treatment performance, which was greater than the ordinary die-cast aluminum alloys with a similar composition. The tensile strength of the aluminum alloys reached up to 310 MPa before heat treatment.

A Review on Traditional Processes and Laser Powder Bed Fusion of Aluminum Alloy Microstructures, Mechanical Properties, Costs, and Applications

“…Also, the development of heat-treatment-free aluminum alloys is one of the important directions of integrated die casting technology. Comparing the tensile properties of AlSiCuMgMn alloy before and after heat treatment, it was found that the tensile strength of the alloy only increased from 310 MPa to 375 MPa after heat treatment, and the elongation decreased from 6.9% to 4.3% [ 49 ].…”

Mechanical Properties of a Structural Component Processed in High-Pressure Die Casting (HPDC) with a Non-Heat-Treated Aluminum Alloy

“…The availability of highly competitive materials and resources has driven the need to keep the aluminum alloy components' costs as low as possible. After searching for research and literature about NHT aluminum alloys, just a few research reports were found [19,20].…”