本文選題：Incoloy800H合金 + 晶界特征分布�。� 參考：《南京理工大學(xué)》2017年碩士論文

【摘要】：Incoloy800H合金具有優(yōu)異的高溫強(qiáng)度、耐高溫氧化及腐蝕能力,廣泛地應(yīng)用于石化工業(yè)領(lǐng)域。然而服役環(huán)境中的腐蝕性氣氛常常會(huì)造成合金的腐蝕破壞,隨著合金服役條件越加復(fù)雜苛刻,對(duì)合金的耐蝕性提出了更高的挑戰(zhàn)。"晶界工程"是根據(jù)晶界設(shè)計(jì)與控制這一概念而提出的,通過形變熱處理工藝優(yōu)化合金中的晶界特征分布,進(jìn)而改善合金與晶界相關(guān)的多種性能。而與晶界有關(guān)的應(yīng)力腐蝕和晶間腐蝕是Incoloy800H合金失效的重要原因,因此,利用晶界工程處理來優(yōu)化Incoloy800H合金的晶界特征分布是改善合金耐腐蝕性能的一個(gè)有效手段。本論文研究了變形量、退火工藝和加工道次對(duì)合金晶界特征分布的影響規(guī)律,從而確定了 Incoloy800H合金晶界工程的最佳形變熱處理工藝參數(shù),并進(jìn)一步研究了晶界特征分布對(duì)合金力學(xué)性能和耐腐蝕性能的影響。主要結(jié)論如下:(1)根據(jù)對(duì)晶界特征分布的調(diào)控以及對(duì)晶間腐蝕傾向的改善效果,確定Incoloy800H合金晶界工程的最佳形變熱處理工藝為15%冷軋變形量后在1050℃退火45min。(2)Incoloy800H合金經(jīng)過形變熱處理后,通過發(fā)生回復(fù)和再結(jié)晶,形成大量Σ3晶界,使得特殊晶界比例從45.53%提高到72.69%,并且打斷了隨機(jī)大角度晶界網(wǎng)絡(luò),從而實(shí)現(xiàn)了晶界特征分布的優(yōu)化。(3)經(jīng)過晶界工程優(yōu)化的Incoloy800H合金的力學(xué)性能相對(duì)于母材得到了提高:抗拉強(qiáng)度提高了 6.7%,延伸率提高了11.3%;在600℃/250MPa條件下,蠕變壽命從251.9h提高到405.8h,穩(wěn)態(tài)蠕變速率由1.84×10~(-7)s~(-1)減小到1.55×10~(-7)s~(-1)。(4)由于低ΣCSL(coincidence site lattice,Σ≤29)晶界相對(duì)于自由大角晶界來說有更好的晶間腐蝕抗力,同時(shí)被低ΣCSL晶界打斷的晶界網(wǎng)絡(luò)能夠抑制晶間腐蝕擴(kuò)展,因此經(jīng)過晶界工程優(yōu)化的合金的耐晶間腐蝕性能得到顯著提高,腐蝕失重速率降低為實(shí)驗(yàn)?zāi)覆牡?/2。
[Abstract]:Incoloy 800H alloy is widely used in petrochemical industry because of its excellent high temperature strength, high temperature oxidation resistance and corrosion resistance. However, the corrosive atmosphere in the service environment often leads to the corrosion damage of the alloy. As the service conditions of the alloy become more complex and demanding, it poses a higher challenge to the corrosion resistance of the alloy. " Grain boundary engineering was proposed according to the concept of grain boundary design and control. The grain boundary characteristic distribution in the alloy was optimized by thermomechanical treatment process, and various properties related to grain boundary were improved. The stress corrosion and intergranular corrosion related to grain boundary are the important causes of incoloy 800H alloy failure. Therefore, it is an effective means to improve the corrosion resistance of incoloy 800H alloy by using grain boundary engineering treatment to optimize the grain boundary characteristic distribution of incoloy 800H alloy. In this paper, the effects of deformation, annealing process and pass on the grain boundary characteristic distribution of incoloy 800H alloy are studied, and the optimum parameters of deformation heat treatment for incoloy 800H alloy grain boundary engineering are determined. The effect of grain boundary characteristic distribution on the mechanical properties and corrosion resistance of the alloy was also studied. The main conclusions are as follows: (1) according to the regulation of grain boundary characteristic distribution and the improvement of intergranular corrosion tendency, The optimum thermomechanical treatment process for incoloy800H alloy grain boundary engineering was determined as 15% cold rolling deformation and annealed at 1050 鈩，

本文編號(hào)：2030052