微合金化元素Zr对5083铝合金组织和性能的影响

在实验室中用井式坩埚炉熔炼铸造了5083和5083+0.1Zr两种铝合金，轧制后在100～450℃范围内退火。通过金相显微镜、显微硬度计、扫描电镜、电子万能试验机、透射电镜对合金的铸态组织、板材纤维组织、力学性能、耐蚀性能、第二相粒子成分进行了分析，研究了微量元素Zr对5083铝合金组织性能的影响。结果表明，添加微量元素Zr能够细化合金组织，与未添加Zr相比，添加0.1Zr的5083合金的铸态晶粒尺寸从123μm降至73μm,并使第二相粒子Al₆Mn(Fe)尺寸变小；同时使晶间腐蚀坑变小，合金耐蚀性得到提高。添加微量元素Zr还能抑制合金板材再结晶，300℃退火1 h无明显再结晶现象；尤其是5083+0.1Zr合金经250℃退火1 h,抗拉强度为389.50 MPa,屈服强度为215.62 MPa,伸长率为18.2%,仍完全满足使用要求。

Effect of microalloying element Zr on microstructure and properties of 5083 aluminum alloy

5083 and 5083+0.1Zr aluminum alloys were melted and cast in laboratory by well crucible furnace, then rolled and annealed in the range of 100-450 ℃. The as-cast microstructure, fibre morphology of the plate, mechanical properties, corrosion resistance and the second phase particle compositions of the alloys were analyzed by means of metallographic microscope, microhardness tester, electronic universal testing machine and scanning electron microscope, so the effect of trace Zr addition on microstructure and properties of the tested alloys was studied. The results show that the addition of trace element Zr can refine the microstructure. Compared with that without Zr, the as-cast grain size of the 5083 alloy with 0.1Zr decreases from 123 μm to 73 μm. The trace addition of Zr can also reduce the size of the second phase Al₆Mn(Fe) particles, reduce the size of intergranular corrosion pits and improve the corrosion resistance of the alloy. Further, the trace addition of Zr can inhibit the recrystallization of the alloy plate, and there is no obvious recrystallization phenomenon when annealed at 300 ℃ for 1 h; and especially, after annealing at 250 ℃ for 1 h, the tensile strength of the 5083+0.1Zr alloy is 389.50 MPa, the yield strength is 215.62 MPa and the elongation is 18.2%, which still fully meet the application requirements.