摘要
采用x射线衍射分析、扫描电镜分析、显微组织分析及拉伸性能测试,研究Gd含量对Mg-6A1-xGd(x=0,0.6%,0.9%,1.2%,1.5%,1.8%)镁合金凝固组织及力学性能的影响。结果表明:Gd含量逐渐增加,α-Mg晶粒尺寸先减小后增大,β-Mg_(17)Al_(12)相从连续网状变为断续网状、颗粒状,且体积数量减少。加入Gd后合金组织中出现了弥散分布的Al_2Gd相。Gd的添加使得合金晶粒得到细化,在Gd含量为0.9%时细化效果最为明显。Mg-6Al-xGd铸态合金的室温抗拉强度呈现先提高后降低的趋势,在Gd的添加量为0.9%时,抗拉强度为210.93 MPa,比未添加Gd元素提高了21.4%。由铸态合金拉伸断口可见大量韧窝和撕裂棱,合金表现为韧-脆混合型断裂特征。
The effects of the content of Gd on microstructure and mechanical properties of cast Mg-6Al-xGd （x=0,0.6, 0.9, 1.2, 1.5, 1.8%, mass fraction） magnesum alloys were investigated using X-ray diffraction analysis, scanning electron microscope, optical microscopy and tensile properties test. The results show that,with the content of Gd increasing gradually, the grain size of a-Mg first decreases and then increases, and the volume and the number offl-MglTAl^2 phase decreases continuously to make the morphology offl-MglTAl^2 change from continuous mesh to intermittent mesh, granular. In addition, A12Gd phases disperse in the microstructure of the alloy. The element of Gd can significantly refine the grain of magnesium alloy, the grain size is the smallest when the content reaches 0.9%. The tensile strength of as-cast Mg-6Al-xGd alloy at room temperature tends to firstly increasing and then decreasing, when the amount of Gd is 0.9%, the tensile strength is 210.93 MPa, which is increased by 21.4% compared with Mg-6Al alloy. The tensile fracture of the as-cast alloy has a lot of dimples and tear ridges, and the alloy is characterized by the mixed fracture of the ductile and brittle.
出处
《铸造技术》
北大核心
2017年第6期1392-1396,共5页
Foundry Technology
