Views: 0 Author: Site Editor Publish Time: 2025-09-19 Origin: Site
I. Overview
Main features: A subeutectic aluminum-silicon-copper alloy, specially optimized for high-pressure die casting (HPDC) processes. It has become one of the most widely used die-cast aluminum alloys in the world due to its excellent casting fluidity, good mechanical strength and relatively good machinability.
Process limitations: It is usually only used in the die-cast state (As-Cast) and cannot undergo solution treatment (T6 treatment), but aging treatment (T5) can be carried out to stabilize dimensions and eliminate internal stress.
II. Chemical Composition (%)
The chemical composition of ADC12 forms the basis of its performance, and its typical range is as follows (based on the JIS H5302 standard) :
Element | Si | Cu | Mg | Fe | Mn | Zn | Ni | Sn | Al |
Composition | 9.6-12.0 | 1.5-3.5 | ≤0.3 | ≤1.3 | ≤0.5 | ≤1.0 | ≤0.5 | ≤0.3 | Balance |
Si: Core element. Significantly enhance the fluidity of the alloy melt, enabling it to easily fill complex and thin-walled mold cavities, while reducing the tendency of solidification shrinkage and hot cracking. However, it will form hard and brittle primary silicon and eutectic silicon phases.
Cu : The main strengthening element. Solid solution in the aluminum matrix forms strengthening phases (such as Al₂Cu), which can significantly enhance the strength, hardness and heat resistance of the alloy. However, it will reduce corrosion resistance and plasticity.
Fe: "The necessary evil". A certain amount of Fe (usually 0.7%-1.0%) can reduce the "welding" (Soldering) between molten aluminum and die steel, protecting the die. However, excessive Fe can form hard and brittle needle-like iron-rich phases (such as β-Al₅FeSi), severely fracture the matrix, and reduce mechanical properties (especially elongation) and subsequent processing performance.
Mg : The content is very low. Trace amounts of Mg can enhance strength, but if the content is too high (>0.3%), it will increase hot brittleness, making casting difficult and preventing T6 heat treatment.
III. Mechanical Properties
The typical mechanical properties of ADC12 are as follows (performance may fluctuate slightly due to factors such as casting wall thickness and cooling rate) :
Features | Value | Notes |
Tensile Strength | ≥ 280MPa | It has good strength performance and can meet the requirements of most structural components. |
Yield Strength | ≥ 150MPa | |
Elongation | ~ 1 - 3% | Poor plasticity is its greatest weakness. Because its structure contains a large amount of hard and brittle silicon and iron-rich phases. |
Brinell Hardness | ~ 75 - 85HB | It has relatively high hardness and good wear resistance. |
Impact Toughness | lower | Not suitable for components subjected to severe impacts. |
Influence of heat treatment:
T5 treatment (artificial aging) : It can slightly increase hardness (about 5-10 HB) and strength, effectively eliminate internal stress, and stabilize dimensions.
T6 treatment (solution treatment + aging) is not allowed: Due to its composition design (low Mg, high Fe/Cu), if high-temperature solution treatment is carried out, the grains close to the eutectic point are prone to overburning (melting), resulting in bubbling, deformation and performance deterioration of the parts.
IV. Summary of Main Features
Advantages
1. Excellent casting performance: It has excellent fluidity, strong resistance to hot cracking, and a high yield of die-cast products.
2. Good mechanical properties: It has relatively good strength and hardness.
3. Good machinability: It has excellent cutting performance and is easy to perform turning, milling, drilling and other processing.
4. Good wear resistance: Due to the presence of hard silicon phase.
Disadvantage
1. Low elongation: Poor plasticity and relatively high brittleness.
2. Non-heat-treatable: Performance cannot be significantly enhanced through T6 treatment.
3. Internal porosity: As a traditional die-cast part, it is inevitable that there will be entrained air inside, so it cannot be welded or used in high-temperature environments.
V. Main Application Fields
ADC12 almost covers all application scenarios of die-cast aluminum alloys, especially dominating the automotive, motorcycle and general machinery fields.
Automotive industry: engine cylinder head, transmission housing, clutch housing, oil pump body, engine bracket, etc.
Motorcycle: engine block, cylinder head, clutch cover, etc.
Electronic communication: routers, server heat dissipation shells, 5G base station filter shells, etc.
Household appliances: washing machine pulleys, motor end covers, various structural frames, etc.
Hardware tools: shells of hand-held electric tools, parts of garden machinery, etc.
VI. Conclusion
ADC12 is an alloy tailor-made for high-pressure casting processes, and its mechanical properties are above average among die-cast aluminum alloys. Its greatest value does not lie in how outstanding its individual performance indicators are, but in the excellent balance achieved among its castability, strength and machinability. It is very suitable for large-scale production of complex-shaped parts that require lightweight and certain strength. When designing and selecting, special attention should be paid to whether its low toughness and poor corrosion resistance meet the requirements of the usage environment.
