挤压铸造和固态热挤压Al-6Zn-2.5Mg-1.8Cu合金的显微组织和力学性能（英文）

发布时间：2018-04-02 17:45

本文选题：铝锌合金　切入点：挤压铸造　出处：《Transactions of Nonferrous Metals Society of China》2015年07期

【摘要】：利用挤压铸造技术,在不同比压下制备Al-6Zn-2.5Mg-1.8Cu合金坯料,然后对性能最好的挤压铸造坯料进行固态热挤压。结果表明:比压从0增加到250 MPa时,树枝晶变得细小而圆整。由于外加压力增加了合金元素的固溶度,因此,MgZn_2相数量减少。当比压从250MPa增加到350 MPa时,合金的晶粒尺寸变大。固态热挤压后,α(Al)树枝晶被明显细化,并且MgZn_2相均匀弥散地分布在合金的显微组织中。固态热挤压后,合金的极限抗拉强度为605.67 MPa,伸长率为8.1%。与金属型铸造合金相比,抗拉强度增加了32.22%,伸长率增加了15.71%。金属型铸造和挤压铸造的断裂方式分别为沿晶断裂和准解理断裂。然而,挤压铸造成形后固态热挤压工艺的合金断裂方式为韧窝断裂。细晶强化作用是合金抗拉强度和伸长率提高的主要原因。
[Abstract]:Squeeze casting technology used in different pressure under the preparation of Al-6Zn-2.5Mg-1.8Cu alloy, then the best performance of squeeze casting billet solid hot extrusion. The results show that the pressure ratio increased from 0 to 250 MPa, the dendrites became small and round. Due to the external pressure increases the solid solubility of alloy elements, therefore, MgZn_2 to reduce the number of phase. When the ratio of pressure increased from 250MPa to 350 MPa, the grain size becomes larger. Solid after hot extrusion, alpha (Al) dendrite was refined obviously, and the MgZn_2 is uniformly distributed in the microstructure of the alloys in the solid state. After hot extrusion, the ultimate tensile strength of the alloy is 605.67 MPa and the elongation of 8.1%. and metal casting alloy, the tensile strength increased by 32.22%, elongation increased the fracture mode of 15.71%. metal casting and extrusion casting were intergranular fracture and quasi cleavage fracture. However, caused by Squeeze Casting The fracture mode of the alloy in the solid state hot extrusion process is the dimple fracture, which is the main reason for the increase of tensile strength and elongation of the alloy.

【作者单位】：沈阳工业大学材料科学与工程学院;哈尔滨工业大学材料科学与工程学院;
【基金】：Project(50971092)supported by the National Natural Science of Foundation of China Project(201202166)supported by the Natural Science Foundation of Education Department of Liaoning Province,China
【分类号】：TG146.21

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