{"id":2275,"date":"2026-01-20T14:50:09","date_gmt":"2026-01-20T06:50:09","guid":{"rendered":"https:\/\/www.hexinmusu.com\/?p=2275"},"modified":"2026-01-20T14:50:10","modified_gmt":"2026-01-20T06:50:10","slug":"zl108-aluminum-alloy-ingot","status":"publish","type":"post","link":"https:\/\/www.hexinmusu.com\/en\/zl108-aluminum-alloy-ingot.html","title":{"rendered":"ZL108 Cast Aluminum Alloy: How Phosphorus Metamorphism and T6 Heat Treatment Shape Top Piston Materials"},"content":{"rendered":"

As an outstanding representative of cast aluminum alloys for pistons, theZL108 (ZAlSi12Cu2Mg1)<\/strong> by means ofExcellent high-temperature strength, low coefficient of thermal expansion and excellent wear and heat resistance<\/strong>and is well known. The alloy is a typicalEutectic aluminum-silicon alloys<\/strong>The piston is optimized for piston parts subjected to severe alternating thermal and mechanical loads in the engine cylinder through complex alloying design and rigorous heat treatment, achieving a precise balance between high-temperature power performance and durability.<\/p>\n\n\n

\n
\"zl108<\/figure>\n<\/div>\n\n\n

The national grade for ZL108 is ZAlSi12Cu2Mg1.<\/strong><\/p>\n\n\n\n

    \n
  • National Standard Grade<\/strong>: According to GB\/T 1173, its grade isZAlSi12Cu2Mg1<\/strong>. The name directly reflects its core alloy system: silicon (Si), copper (Cu), and magnesium (Mg).<\/li>\n\n\n\n
  • Industry\/Enterprise Code<\/strong>:ZL108<\/strong> is the designation commonly used for this material in the field of engine design and manufacturing.<\/li>\n\n\n\n
  • typical situation<\/strong>: it almost always starts withT6 condition (solid solution treatment + full artificial aging)<\/strong> Use to obtain the best overall performance, especially at high temperatures.<\/li>\n<\/ul>\n\n\n\n

    ZL108 Aluminum Alloy Composition Table<\/strong><\/p>\n\n\n\n

    elemental<\/th>Content range (wt%)<\/th>functional role<\/th><\/tr><\/thead>
    Silicon (Si)<\/strong><\/td>11.0-13.0<\/strong><\/td>Hypereutectic content<\/strong>.. Provides low thermal expansion and high wear resistance, but the incipient silicon phase needs to be refined by phosphorus (P) metamorphism.<\/td><\/tr>
    Copper (Cu)<\/strong><\/td>1.0-2.0<\/strong><\/td>Main high-temperature strengthening elements<\/strong>. Formation of heat-resistant Al\u2082Cu phases significantly improves high-temperature strength and hardness.<\/td><\/tr>
    Magnesium (Mg)<\/strong><\/td>0.4-1.0<\/strong><\/td>Key Enhancement Elements<\/strong>. The Mg\u2082Si phase is formed, which together with Cu provides room and high temperature strength.<\/td><\/tr>
    Manganese (Mn)<\/strong><\/td>0.3-0.9<\/td>Improves heat resistance, forms heat-resistant phases, and mitigates the harmful effects of iron (Fe).<\/td><\/tr>
    Nickel (Ni)<\/strong><\/td>0.3-0.9<\/td>Important heat-resistant elements<\/strong>. Forms a stable heat-resistant phase to enhance high-temperature creep resistance.<\/td><\/tr>
    Titanium (Ti)<\/strong><\/td>\u22640.20<\/td>Grain refiner.<\/td><\/tr>
    Aluminum (Al)<\/strong><\/td>tolerance (i.e. allowed error)<\/td>Substrate material.<\/td><\/tr><\/tbody><\/table><\/figure>\n\n\n\n

    ZL108 Physical and Mechanical Properties Parameter Table (metal mold casting, typical value for T6 state)<\/strong><\/p>\n\n\n\n

    Performance indicators<\/th>Numerical range<\/th>Core Strengths Explained<\/th><\/tr><\/thead>
    intensity<\/strong><\/td>2.68-2.70 g\/cm\u00b3<\/td>--<\/td><\/tr>
    Room temperature tensile strength (Rm)<\/strong><\/td>250-280 MPa<\/strong><\/td>High strength level to meet piston structural loading requirements.<\/td><\/tr>
    High temperature tensile strength (250\u00b0C)<\/strong><\/td>\u2265 120 MPa<\/strong><\/td>Core Advantages<\/strong>, maintains sufficient strength at high temperatures to prevent cracking or deformation of the top of the piston.<\/td><\/tr>
    Elongation (A)<\/strong><\/td>\u2264 1.0%<\/strong><\/td>Poor plasticity is inherent in its highly strengthened, per-eutectic organization.<\/td><\/tr>
    Brinell hardness (HB)<\/strong><\/td>100-130<\/td>high stiffness<\/strong>The product is designed to ensure excellent abrasion resistance.<\/td><\/tr>
    Coefficient of linear expansion (20-200\u00b0C)<\/strong><\/td>18.5-20.0 \u00d7 10-\u2076\/\u00b0C<\/strong><\/td>Core Advantages<\/strong>It is lower than most aluminum alloys, and it matches better with cylinder liner, which is good for controlling cylinder clearance.<\/td><\/tr>
    volumetric stability<\/strong><\/td>\u4f18<\/strong><\/td>The T6 treatment results in minimal dimensional changes under long-term use.<\/td><\/tr><\/tbody><\/table><\/figure>\n\n\n\n

    Performance Enhancement Paths and Technology Keys<\/strong>
    The realization of the ZL108's performance relies on a combination of sophisticated and interlocking processes:<\/p>\n\n\n\n

      \n
    1. Precise control of alloy composition<\/strong>: The contents of Si, Cu, Mg and Ni need to be precisely matched to form an optimal combination of heat-resistant phases. It must be strictly controlledPhosphorus (P) Deterioration Treatment<\/strong>in order to refine the eutectic organization of thenascent silicon phase<\/strong>This is a prerequisite for good mechanical properties and machinability.<\/li>\n\n\n\n
    2. Proprietary heat treatment system (T6)<\/strong>:\n
        \n
      • solid solution treatment<\/strong>: Typically performed at 505\u00b15\u00b0C to allow for full dissolution of the soluble fortified phase.<\/li>\n\n\n\n
      • artificial time limit<\/strong>: Prolonged aging at higher temperatures (e.g. 200-220\u00b0C) for the formation of stable reinforcing phases.Specifically optimized for high temperature performance and tissue stability<\/strong>.<\/li>\n<\/ul>\n<\/li>\n\n\n\n
      • Advanced Casting Process<\/strong>: AdoptionMetal type gravity casting<\/strong>\u6216Low-pressure casting<\/strong>, in order to obtain a dense, uniform cast state organization. Good casting process is the basis for subsequent heat treatment and performance.<\/li>\n<\/ol>\n\n\n\n

        Corresponding international grades<\/strong>
        As a classic piston alloy, it has its counterpart in national standards:<\/p>\n\n\n\n

          \n
        • Chinese national standard<\/strong>:ZAlSi12Cu2Mg1<\/strong> (GB\/T 1173)<\/li>\n\n\n\n
        • American Standard<\/strong>:A332.0<\/strong> (ASTM, very close)<\/li>\n\n\n\n
        • EU standard<\/strong>:EN AC-48000<\/strong> (EN 1706)<\/li>\n\n\n\n
        • Japanese Standard<\/strong>:AC9A<\/strong> \u6216 AC9B<\/strong> (JIS)<\/li>\n<\/ul>\n\n\n\n

          Application of ZL108 in the foundry industry<\/strong>
          Its applications are highly specialized, focusing almost exclusively on theCore hot end components for internal combustion engines<\/strong>:<\/p>\n\n\n\n

            \n
          1. Pistons (absolute mainstream applications)<\/strong>\n
              \n
            • Diesel Engine Pistons<\/strong>: Pistons for medium- and heavy-duty trucks, construction machinery, and marine diesel engines (utilizing their excellent high-temperature strength and wear resistance).<\/li>\n\n\n\n
            • High Performance Gasoline Engine Pistons<\/strong>: Pistons for large displacement, high boost, high power density gasoline engines.<\/li>\n\n\n\n
            • Modified & Racing Pistons<\/strong>: Where there are extreme requirements for heat resistance and strength.<\/li>\n<\/ul>\n<\/li>\n\n\n\n
            • Other heat-resistant and wear-resistant parts<\/strong>\n
                \n
              • Engine rotor<\/strong>: Rotating parts of certain specialized engines.<\/li>\n\n\n\n
              • Compressor pistons<\/strong>: High pressure air compressor.<\/li>\n\n\n\n
              • Brake Caliper Pistons<\/strong>(in a few high-performance requirements).<\/li>\n<\/ul>\n<\/li>\n<\/ol>\n\n\n\n

                ZL108 Aluminum Alloy Frequently Asked Questions<\/strong><\/p>\n\n\n\n

                Q1: What is the biggest technical difficulty of ZL108?<\/strong><\/p>\n\n\n\n

                  \n
                • Casting and Deterioration<\/strong>. Due to its hypereutectic composition, the melt precipitates coarsePrimary silicon crystals<\/strong>, which severely cuts into the matrix, leading to dramatic performance degradation and machining difficulties. This must be achieved by precisePhosphorus (P) Deterioration Treatment<\/strong>(e.g., by adding Cu-P intermediate alloys) to refine the primary silicon, which is ZL108 production in theCore technology threshold<\/strong>.<\/li>\n<\/ul>\n\n\n\n

                  Q2: Why is the elongation of ZL108 so low?<\/strong><\/p>\n\n\n\n

                    \n
                  • This is the first time it has been awardedHigh strength, high hardness, low coefficient of expansion<\/strong>The inevitable price to pay. The per-eutectic silicon phase and the large number of heat-resistant intermetallics (containing Cu, Mg, Ni), while providing the desired high-temperature properties, also significantly reduce the plasticity and toughness of the material.<\/li>\n<\/ul>\n\n\n\n

                    Q3\uff1aWhat surface treatment is required for ZL108 piston?<\/strong><\/p>\n\n\n\n

                      \n
                    • To further enhance performance, ZL108 pistons are often given a combination of surface treatments:\n
                        \n
                      • anodic oxidation<\/strong>: Forms a hard aluminum oxide film on the top ring groove of the piston or on the surface of the combustion chamber to increaseHeat, wear and abrasion resistance<\/strong>.<\/li>\n\n\n\n
                      • Graphite Coating<\/strong>: Spray solid lubricant on the piston skirt to improve wear and friction reduction.<\/li>\n\n\n\n
                      • electroplated<\/strong>: e.g. tinned to facilitate initial break-in.<\/li>\n<\/ul>\n<\/li>\n<\/ul>\n\n\n\n

                        Q4: How does ZL108 compare to common piston materials such as ZL109 or eutectic alloys?<\/strong><\/p>\n\n\n\n

                          \n
                        • ZL108 (per eutectic)<\/strong>:Higher Si content (11-13%)<\/strong>(math.) genusLowest coefficient of thermal expansion and best abrasion resistance<\/strong>, but the casting and machining is the most difficult and costly. Suitable forThe heat load is the most severe<\/strong>The occasion.<\/li>\n\n\n\n
                        • ZL109 (eutectic\/sub-eutectic) and similar alloys<\/strong>: Slightly lower Si content (8-11%), better casting performance, better machinability, better overall mechanical properties (especially toughness), is the most widely used piston material.Coefficient of thermal expansion and abrasion resistance slightly inferior to ZL108<\/strong>.<\/li>\n<\/ul>\n\n\n\n

                          Q5: What are the special requirements for machining ZL108?<\/strong><\/p>\n\n\n\n

                            \n
                          • because ofHigh hardness with hard silicon phase<\/strong>, with poor cutting and machinability, is known as \u201cHard-to-cut aluminum alloys<\/strong>\u201d\u3002\n
                              \n
                            • cutters<\/strong>: must be usedPCD (Polycrystalline Diamond) Cutting Tools<\/strong>or quality coated carbide cutters.<\/li>\n\n\n\n
                            • parameters<\/strong>: High cutting speeds and small feeds are used.<\/li>\n\n\n\n
                            • hardened<\/strong>: Diamond wheels are the only cost-effective choice for areas such as ring grooves.<\/li>\n<\/ul>\n<\/li>\n<\/ul>","protected":false},"excerpt":{"rendered":"

                              As an outstanding representative of cast aluminum alloys for pistons, ZL108 (ZAlSi12Cu2Mg1) is known for its excellent high-temperature strength, low coefficient of thermal expansion, and outstanding wear and heat resistance. The alloy is a typical perovskite aluminum-silicon alloy, optimized for piston components subjected to severe alternating thermal and mechanical loads in engine cylinders through complex alloying design and rigorous heat treatment, achieving a precise balance between high-temperature dynamic performance and durability. The corresponding national grade for ZL108 is ZAlSi12Cu2Mg1. ZL108 Aluminum Alloy Composition Table Element Content Range (wt%) Functional Role Silicon (Si) 11.0-13.0 Hypereutectic content. Provides low thermal expansion and high wear resistance, but the incipient silicon phase needs to be refined by phosphorus (P) metamorphism. Copper (Cu) 1.0-2.0 Mainly high-temperature strong ...<\/p>","protected":false},"author":1,"featured_media":2276,"comment_status":"closed","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":[],"categories":[21],"tags":[121,89],"class_list":["post-2275","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-about-news","tag-common-cast-aluminum-alloys","tag-aluminium-alloy"],"_links":{"self":[{"href":"https:\/\/www.hexinmusu.com\/en\/wp-json\/wp\/v2\/posts\/2275","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.hexinmusu.com\/en\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.hexinmusu.com\/en\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.hexinmusu.com\/en\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/www.hexinmusu.com\/en\/wp-json\/wp\/v2\/comments?post=2275"}],"version-history":[{"count":0,"href":"https:\/\/www.hexinmusu.com\/en\/wp-json\/wp\/v2\/posts\/2275\/revisions"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/www.hexinmusu.com\/en\/wp-json\/wp\/v2\/media\/2276"}],"wp:attachment":[{"href":"https:\/\/www.hexinmusu.com\/en\/wp-json\/wp\/v2\/media?parent=2275"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.hexinmusu.com\/en\/wp-json\/wp\/v2\/categories?post=2275"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.hexinmusu.com\/en\/wp-json\/wp\/v2\/tags?post=2275"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}