AM50-x（Zn,Y）鎂合金組織性能與凝固行為

AM50-x（Zn,Y）鎂合金組織性能與凝固行為MICROSTRUCTURE, MECHANICAL PROPERTIES AND SOLIDIFICATION BEHAVIOR OF AM50-x (Zn, Y) MAGNESIUM ALLOYS

將 Zn 和 Y 元素以原子比為 6:1 的形式加入 AM50 合金中, 并采用金屬型鑄造成形, 利用 OM, SEM, EDS, XRD, 熱分析法及拉伸實驗研究了 AM50-x(Zn, Y) (x=0, 2, 3, 4, 5, 質(zhì)量分數(shù), %)合金的顯微組織、凝固行為及力學(xué)性能. 結(jié)果表明: 向 AM50 合金中按原子比為 6 的形式加入 Zn 和 Y元素后, 組織得到明顯細化, 組織中并未形成 Mg3Zn6Y 準晶相, 而形成了顆粒狀的 Al6YMn6相和細小的 Al2Y 相, 其中 Al6YMn6相尺寸隨著 Zn 和 Y元素含量的增加而增大; 當 x≥3 時, 在組織中 β 相的周圍逐漸形成層片狀的 Φ-Mg21(Zn, Al)17相, 且其數(shù)量逐漸增加. 熱分析結(jié)果表明, Φ-Mg21(Zn, Al)17相約在 354 ℃通過包晶反應(yīng)形成, 其中 α-Mg 和 β 相析出溫度隨著 x 的增加而降低. 由于 Al6YMn6相、Al2Y 相和 Φ-Mg21(Zn, Al)17相的形成, 使得 β 相的尺寸減小、數(shù)量減少; 當 x=4 時, 合金組織最為細小, 且合金力學(xué)性能達到最優(yōu), 其抗拉強度、屈服強度和伸長率分別為 206.63 MPa, 92.50 MPa 和 10.04%.

As the lightest metallic structural material, magnesium alloys were widely used in automotive, aerospace, electronic equipment and other fields. Among commercial magnesium alloys, AM series were commonly used due to excellent ductility and energy absorption. However, their relatively poor strength greatly restricted their extended use. In order to improve mechanical properties of AM50 alloy, the Zn and Y elements were added into the AM50 alloy in the form of atomic ratio of 6:1 by the permanent mold casting. The microstructure, solidification behavior and mechanical properties of AM50-x(Zn, Y) (x=0, 2, 3, 4, 5, mass fraction, %) alloys were investigated by OM, SEM, EDS, XRD, thermal analysis and tensile tests. The results indicated that addition of Zn and Y elements with an atomic ratio of 6:1 to AM50 alloy, the microstructures were obviously refined, and the quasicrystal I-Phases (Mg3Zn6Y) cannot form. In addition, the granular Al6YMn6 phase and fine Al2Y phase were formed in the microstructure, and the size of Al6YMn6 phase increased with increasing the Zn and Y content. The Φ-Mg21(Zn, Al)17 phase with lamellar structure was formed around β phase when x≥3, and its amount increased with increasing the Zn and Y addition. Thermal analysis results show that the Φ-Mg21(Zn, Al)17 phase was formed at 354 ℃ by the peritectic reaction, in which the precipitation temperatures of α-Mg and β phase were decreased with the increase of x content. Due to the formation of Al6YMn6, Al2Y and Φ-Mg21(Zn, Al)17 phases, the size and amount of the β phase was decreased. For AM50-4 (Zn, Y) alloy, the microstructure was greatly refined, and the ultimate tensile strength, yield strength and elongation of the alloy reached to the maximum, 206.63 MPa, 92.50 MPa and 10.04%, respectively.

全文下載：https://pan.baidu.com/s/1i5MOJDN