累积多道次连续挤压对纯铜组织和力学性能的影响

    Effect of Cumulative Multipass Continuous Extrusion on Microstructure and Mechanical Properties of Pure Copper

    • 摘要: 采用累积多道次连续挤压工艺,以连续进料的方式对纯铜进行多道次连续挤压,利用光学显微镜、扫描电子显微镜(SEM)、电子万能材料试验机观察纯铜杆料的微观组织演变,测试力学性能。探讨挤压道次对纯铜杆料微观组织和力学性能的影响。结果表明:经过一道次连续挤压,纯铜杆料抗拉强度由178.21 MPa提升至239.61 MPa,伸长率由41.72%提升至52.43%。随着挤压道次的增加,纯铜杆料的抗拉强度和伸长率先升高后降低,经过二道次连续挤压,纯铜杆料的抗拉强度和伸长率达到最大值,分别为248.03 MPa和56.51%。随着挤压道次的增加,纯铜杆料平均晶粒尺寸先减小后逐渐增大。经过二道次连续挤压后纯铜杆料平均晶粒尺寸最小,拉伸断口韧窝最深且分布均匀,综合力学性能最优。

       

      Abstract: The cumulative multipass continuous extrusion process was used to conduct multipass continuous extrusion for pure copper by means of continuous feeding. The microstructure evolution and mechanical properties of pure copper rod were observed and tested by optical microscope, scanning electron microscope(SEM) and electronic universal material testing machine, and the effect of extrusion pass on the microstructure and mechanical properties of pure copper rod was discussed.The results show that after one continuous extrusion, the tensile strength of pure copper rod material increases from 178.21 MPa to 239.61 MPa, and the elongation increases from 41.72% to 52.43%. As the number of extrusion passes increases, the tensile strength and elongation of pure copper rod material first increase and then decrease. After two cumulative extrusion passes, the tensile strength of pure copper rod material reaches its maximum value, which is 248.03 MPa and 56.51%,respectively. As the number of extrusion passes increases, the average grain size of pure copper rod material first decreases and then gradually increases. After two continuous extrusion passes, the average grain size is smallest, the dimples of the tensile fracture is deepest and evenly distributed, and the overall mechanical properties are best.

       

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