合金化对H62黄铜组织和性能影响

发布时间：2018-05-11 17:32

本文选题：H62黄铜 + 稀土　；参考：《济南大学》2017年硕士论文

【摘要】：被广泛应用于工业和生活中,例如散热器、海底管道、水管等,是因为它具有良好的加工工艺性、耐蚀性、力学性能、导电以及价格低廉等优点。但是,其在使用过程中,会出现脱锌腐蚀的现象,导致黄铜的机械性能下降,使其使用寿命大大缩短,从而带来了潜在的安全隐患。因此,开发出新成分的高强度、耐腐蚀黄铜已成为目前研究的重点。本文以H62黄铜为研究对象,采用常规铸造方法添加Nd、Sm、B合金元素以及复合加入Nd和B元素,旨在提高H62黄铜的力学性能和耐蚀性能。本文采用金相显微镜、扫描电镜(SEM)、X-射线能谱分析(EDS)、X-射线衍射(XRD)、拉伸实验、静态腐蚀试验和电化学腐蚀试验等手段来研究合金化、细化变质以及复合处理对H62黄铜的组织和性能的影响。得到的主要结论如下:在H62黄铜中添加稀土Nd和Sm元素都使合金的强度、硬度上升。与H62黄铜相比,加入1.0wt.%Nd,抗拉强度和硬度分别提高了17.2%和62.5%;加入1.0wt.%Sm,抗拉强度、屈服强度和硬度分别提高了25.1%、50%和78.1%。向黄铜中加入Nd和Sm后,合金的金相组织相差不大,均由长条状或块状的α-Cu0.64Zn0.36相和短棒状的β′-CuZn相组成。其中Nd和Sm的添加量均为1.0wt.%时,β′-Cu Zn相平均晶粒尺寸分别为30μm和20μm,合金组织都得到细化,但Sm对H62黄铜的细化效果比Nd明显。Nd和Sm加入到H62黄铜中,改变了β′相的分布和尺寸,在黄铜中,β′相的强度和硬度高,使H62黄铜的抗拉强度和硬度提高。同时,加入Nd和Sm后,H62黄铜的腐蚀电位得到提高,静态腐蚀速率和腐蚀电流密度下降,其耐蚀性能提高。与H62黄铜相比,Nd添加量为1.0wt.%时,腐蚀电位提高了43.9%,静态腐蚀速率和腐蚀电流密度分别下降了31.3%和1.8%;Sm添加量为1.0wt.%时,腐蚀电位提高了6.8%,静态腐蚀速率和腐蚀电流密度分别下降了19.6%和1.5%。向H62黄铜中加入B元素,合金微观组织中α-Cu0.64Zn0.36相由长条状转变为等轴状,β′-CuZn相较H62黄铜减少,分布在晶界处。B元素的添加量为0.1wt.%时,合金组织中出现少量的等轴晶,平均晶粒尺寸为30μm。此时合金的塑性提高,抗拉强度和硬度下降,与H62黄铜相比,塑性提高了17.6%,抗拉强度和硬度分别下降了10.1%和12.5%。B的原子半径远小于Zn的原子半径,黄铜发生脱锌腐蚀时,B可以填充Zn空位,抑制黄铜的脱锌腐蚀。当B的添加量为0.05wt.%时,H62黄铜的腐蚀电位提高,静态腐蚀速率和腐蚀电流密度下降,与H62黄铜相比,腐蚀电位提高了30.1%,静态腐蚀速率和腐蚀电流密度分别下降了27.6%和4.5%。将Nd和B复合加入到H62黄铜,合金的塑性得到提高,抗拉强度和硬度下降。向黄铜中添加Nd和B,合金微观组织中β′-Cu Zn相较H62黄铜减少,α-Cu0.64Zn0.36相由长条状转变为树枝状。在黄铜中,α相是面心立方结构,有较高的塑性,使合金的塑性提高。添加0.05wt.%B+0.2wt.%Nd时,合金的抗拉强度为320MPa,硬度为56HBW,伸长率为42%,与H62相比,抗拉强度和硬度分别下降了5.3%和12.5%,伸长率提高了23.5%。此时,合金的腐蚀电位得到提高,静态腐蚀速率和腐蚀电流密度下降,其耐蚀性能提高,与H62黄铜相比,腐蚀电位提高了35.0%,静态腐蚀速率和腐蚀电流密度分别下降了32%和3.1%。
[Abstract]:It is widely used in industry and life, such as radiators, seabed pipes, pipes and so on. It is because of its good processing technology, corrosion resistance, mechanical properties, electrical conductivity and low price. However, in the process of use, the phenomenon of dezinking corrosion will occur, resulting in the decline of the mechanical properties of brass, so that its service life is greatly reduced. Therefore, the development of high strength and corrosion resistant brass with new ingredients has become the focus of research. This paper takes H62 brass as the research object, adding Nd, Sm, B alloy elements and adding Nd and B elements with conventional casting methods, aiming at improving the mechanical and corrosion resistance of H62 brass. Using metallographic microscope (SEM), X- ray energy spectrum analysis (EDS), X- ray diffraction (XRD), tensile test, static corrosion test and electrochemical corrosion test, the effects of alloying, refining and compound treatment on the microstructure and properties of H62 brass are studied. The main conclusions are as follows: the addition of rare earth Nd to H62 brass and the addition of rare earth Nd are the main conclusions. Sm element makes the strength and hardness of the alloy increase. Compared with H62 brass, the tensile strength and hardness of the alloy are increased by 17.2% and 62.5%, respectively, and the tensile strength, yield strength and hardness are increased by 25.1% respectively. After adding Nd and Sm to the brass, the alloy's metallographic structure is not much different, all from the strip or lump shape. When the addition of Nd and Sm is 1.0wt.%, the average grain size of the beta '-Cu Zn phase is 30 u m and 20 micron, respectively. The microstructure of the alloy is refined, but the refining effect of Sm to H62 brass is better than that of Nd. The distribution and size of the beta' phase are changed, in brass, in brass. At the same time, the tensile strength and hardness of H62 brass are higher, and the corrosion potential of H62 brass is increased after adding Nd and Sm, and the corrosion resistance and corrosion resistance of the H62 brass are improved. The corrosion potential is increased by 43.9% when Nd addition is 1.0wt.%, and the static corrosion rate and the corrosion rate are higher than that of H62 brass. The corrosion current density decreased by 31.3% and 1.8%, respectively, when the addition of Sm was 1.0wt.%, the corrosion potential increased by 6.8%, the static corrosion rate and the corrosion current density decreased by 19.6% and 1.5%. to H62 brass to add B element, and the alpha -Cu0.64Zn0.36 phase changed from the strip to the equiaxed form in the alloy microstructure, and the beta '-CuZn phase was less than the H62 brass. When the amount of.B element added at the grain boundary is 0.1wt.%, a small amount of equiaxed grains appear in the alloy structure. The average grain size is 30 u M. at this time, the plasticity of the alloy increases, the tensile strength and hardness decrease. Compared with the H62 brass, the plasticity is increased by 17.6%, the tensile strength and hardness drop by 10.1% and 12.5%.B, respectively, and the atomic radius is far less than Zn atoms. When the radius and brass are dezine corrosion, B can fill the Zn vacancy and inhibit the dezine corrosion of brass. When the addition of B is 0.05wt.%, the corrosion potential of H62 brass increases, the static corrosion rate and corrosion current density decrease, and the corrosion potential is increased by 30.1% compared with H62 brass, and the static corrosion rate and corrosion current density decrease by 27.6%, respectively. With the addition of Nd and B to H62 brass, the plasticity of the alloy is improved, the tensile strength and hardness decrease. Nd and B are added to the brass, and the microstructure of the alloy is reduced to the H62 brass in the microstructure of the alloy, and the alpha -Cu0.64Zn0.36 phase is transformed from the strip to the dendrite. In brass, the alpha phase is a face centered cubic structure with high plasticity, making alloy. When 0.05wt.%B+0.2wt.%Nd is added, the tensile strength of the alloy is 320MPa, the hardness is 56HBW and the elongation is 42%. The tensile strength and hardness of the alloy decreased by 5.3% and 12.5% respectively compared with the H62. The corrosion potential of the alloy was increased at this time, the corrosion potential and corrosion current density of the alloy decreased, and the corrosion resistance of the alloy was increased. Compared with H62 brass, the corrosion potential increased by 35%, and the static corrosion rate and corrosion current density decreased by 32% and 3.1%. respectively.

【学位授予单位】：济南大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TG146.11

【参考文献】