本文選題：多主元高熵合金 + 相組成��； 參考：《南昌大學(xué)》2017年碩士論文

【摘要】：相比傳統(tǒng)合金,多主元高熵合金不僅由簡(jiǎn)單的相組成,而且還具有高硬度、高強(qiáng)度、良好抗磨性及耐腐蝕性等優(yōu)異的性能,因此多主元高熵合金逐漸成為新型金屬材料領(lǐng)域中備受關(guān)注的研究熱點(diǎn)。本文以FeCoNiCuAl系多主元高熵合金為研究對(duì)象,采用了X射線衍射儀(XRD)、金相顯微鏡(OM)、掃描電子顯微鏡(SEM)、能譜儀(EDS)、顯微硬度測(cè)試、壓縮性能測(cè)試等實(shí)驗(yàn)分析方法,研究了Al和Cu含量對(duì)FeCoNiCuAl系多主元高熵合金組織結(jié)構(gòu)(相結(jié)構(gòu)及組成、微觀組織、元素分布)和性能(硬度、壓縮性)的影響。同時(shí),本文還研究了退火溫度對(duì)冷軋態(tài)FeCoNiCuAl_(0.5)高熵合金組織結(jié)構(gòu)和硬度的影響。結(jié)果表明:(1)在FeCoNiCuAl_x(x=0.5、1.0、1.5、2.0)多主元高熵合金中,四種合金都由簡(jiǎn)單的fcc結(jié)構(gòu)和bcc結(jié)構(gòu)相組成,但隨著Al含量的增加,bcc相體積分?jǐn)?shù)增多,fcc相體積分?jǐn)?shù)減少,當(dāng)x=2.0時(shí),合金主要為bcc相,只有少量的fcc相。四種合金鑄態(tài)下均為典型的樹枝晶組織,枝晶間存在明顯的Cu富集,并且隨著Al含量的增加加劇了Cu元素的偏析程度。同時(shí),FeCoNiCuAl_x合金的顯微硬度和屈服強(qiáng)度也隨Al含量的增加而增大,FeCoNiCuAl2.0合金的顯微硬度和屈服強(qiáng)度達(dá)到了最大值,分別為568 HV和1435 MPa,但是該合金體系的塑性卻隨Al含量的增加而呈降低的趨勢(shì)。(2)在FeCoNiAlCu_x(x=0.5、0.8、1.0、1.5)多主元高熵合金中,四種合金也均由fcc結(jié)構(gòu)相和bcc結(jié)構(gòu)相組成,但隨著Cu含量的增加,fcc相體積分?jǐn)?shù)增多,而bcc相體積分?jǐn)?shù)減少;四種合金鑄態(tài)下均為典型的樹枝晶組織,枝晶間存在明顯的Cu富集,并且隨著Cu含量的增加而加劇了Cu元素在枝晶間的富集,但在枝晶內(nèi)沒有變化。同時(shí),FeCoNiAlCu_x合金的顯微硬度和屈服強(qiáng)度均隨Cu含量的增加而降低,FeCoNiAlCu0.5合金的顯微硬度最高,達(dá)到569 HV,FeCoNiAlCu0.8合金的屈服強(qiáng)度最大,為1256 MPa,但是該合金體系的塑性卻是隨著Cu含量的增加而顯著提高,FeCoNiAlCu1.5合金的塑性最好,其壓縮應(yīng)變高達(dá)36.1%。此外,Cu元素含量對(duì)該合金體系的斷裂類型也有明顯的影響,從合金FeCoNiAlCu0.5的解理斷裂演變到合金FeCoNiAlCu1.5的塑性斷裂。(3)對(duì)冷軋態(tài)FeCoNiCuAl_(0.5)多主元高熵合金進(jìn)行不同溫度退火處理。當(dāng)退火溫度為700-900℃時(shí),合金的顯微組織形貌均表現(xiàn)為典型的樹枝晶組織,枝晶由fcc相構(gòu)成,枝晶間由bcc相構(gòu)成。但當(dāng)退火溫度升高到1000℃時(shí),合金中只含有fcc相,同時(shí)促進(jìn)了元素的均勻分布,消除了部分枝晶偏析。此外,合金的顯微硬度隨退火溫度升高而呈先增大后減小趨勢(shì),在700℃時(shí),合金顯微硬度達(dá)到最大值為418 HV,且經(jīng)過退火處理的合金的顯微硬度均高于冷軋態(tài)的顯微硬度。
[Abstract]:Compared with conventional alloys, multi-principal element high-entropy alloys not only consist of simple phases, but also have excellent properties such as high hardness, high strength, good wear resistance and corrosion resistance. Therefore, multi-principal element high-entropy alloys have gradually become the focus of research in the field of new metal materials. In this paper, FeCoNiCuAl multi-principal component high entropy alloy is studied. The methods of X-ray diffraction (XRD), metallographic microscope (OM), scanning electron microscope (SEM), energy spectrometer (EDS), microhardness test, compression property test, etc. The effects of Al and Cu contents on the microstructure (phase structure and composition, microstructure, element distribution) and properties (hardness, compressibility) of FeCoNiCuAl multiprincipal element high entropy alloy were studied. At the same time, the effect of annealing temperature on the microstructure and hardness of cold-rolled FeCoNiCuAl0.5 high entropy alloy was studied. The results show that: (1) in FeCoNiCuAlx multiprincipal element high entropy alloy, the four alloys are composed of simple fcc structure and bcc structure phase, but with the increase of Al content, the volume fraction of FCC phase decreases. When x2.0, the alloy is mainly bcc phase. There is only a small amount of fcc phase. The dendritic structure of the four alloys is typical in the as-cast state. There is obvious Cu enrichment between the dendrites, and the segregation degree of Cu is aggravated with the increase of Al content. At the same time, the microhardness and yield strength of FeCoNiCuAlx alloy increased with the increase of Al content, and the microhardness and yield strength of FeCoNiCuAl2.0 alloy reached the maximum value. The plasticity of the alloy system decreased with the increase of Al content. (2) in FeCoNiAlCux (0.50.80.81.50) multiprincipal element high entropy alloy, the four alloys also consist of fcc structure phase and bcc structure phase. However, with the increase of Cu content, the volume fraction of FCC phase increases, while the volume fraction of bcc phase decreases. With the increase of Cu content, the enrichment of Cu elements between dendrites is intensified, but there is no change in the dendrite. At the same time, the microhardness and yield strength of FeCoNiAlCux alloy decreased with the increase of Cu content, and the highest microhardness of FeCoNiAlCu0.5 alloy reached the highest yield strength of 569 HVN FeCoNiAlCu0.8 alloy. The ductility of the alloy system is 1256 MPA, but the plasticity of FeCoNiAlCu1.5 alloy is the best with the increase of Cu content, and the compressive strain of the alloy is as high as 36.1. In addition, the content of Cu also has a significant effect on the fracture type of the alloy system, from cleavage fracture of FeCoNiAlCu0.5 to plastic fracture of FeCoNiAlCu1.5. (3) annealing of cold-rolled FeCoNiCuAl0.5 multi-principal element high entropy alloy at different temperatures. When annealing temperature is 700-900 鈩，

本文編號(hào)：2086864