本文選題：相變儲(chǔ)能鋁合金熔體 + 304不銹鋼�。� 參考：《中國(guó)石油大學(xué)(華東)》2015年碩士論文

【摘要】：相變儲(chǔ)能技術(shù)應(yīng)用的成功與否,不僅與儲(chǔ)能材料的熱物性能有關(guān),還與儲(chǔ)能材料熔體與容器材料的相容性有很大關(guān)系。已有研究表明:相變儲(chǔ)能鋁合金具有優(yōu)良的熱物性能,在太陽(yáng)能熱發(fā)電等高溫儲(chǔ)能方面具有廣闊的應(yīng)用前景,但其在高溫液態(tài)環(huán)境下對(duì)鐵基容器表面侵蝕嚴(yán)重,制約了其進(jìn)一步發(fā)展和應(yīng)用。針對(duì)上述問(wèn)題,本文選用Al-12Si-xCu、Al-xSi-10Cu及Al-12Si-15Cu-2Mg等八種合金為儲(chǔ)能材料,以304不銹鋼為容器材料進(jìn)行侵蝕試驗(yàn),分別研究了在不同溫度、時(shí)間及組元元素(Cu、Si和Mg)的條件下儲(chǔ)能鋁合金熔體對(duì)304不銹鋼的侵蝕行為,并結(jié)合XRD分析、金相組織分析及EDS分析等揭示了儲(chǔ)能鋁合金熔體對(duì)304不銹鋼的侵蝕機(jī)理,為降低相變儲(chǔ)能鋁合金熔體的侵蝕性提供了試驗(yàn)及理論依據(jù)。對(duì)于本論文所研究的八種合金而言,當(dāng)侵蝕時(shí)間為24h,侵蝕溫度范圍為580℃~660℃時(shí),304不銹鋼的侵蝕速率和侵蝕層厚度都隨溫度的升高而增大,且當(dāng)溫度超過(guò)640℃時(shí),侵蝕速率和侵蝕層厚度大幅度增加,可見侵蝕溫度對(duì)侵蝕行為影響顯著,低溫有利于降低鋁合金熔體的侵蝕性。對(duì)于本論文所研究的八種儲(chǔ)能合金而言,當(dāng)侵蝕溫度為620℃,侵蝕時(shí)間由24h延長(zhǎng)至120h時(shí),侵蝕速率隨時(shí)間的延長(zhǎng)而降低,降低到一定程度后則保持相對(duì)穩(wěn)定,即達(dá)到動(dòng)態(tài)平衡狀態(tài)。在Al-12Si-xCu(0≤x≤15)合金熔體對(duì)304不銹鋼的侵蝕過(guò)程中,隨著Cu含量的增加,侵蝕速率和侵蝕層厚度都逐漸減小。在Al-xSi-10Cu(6≤x≤15)合金熔體對(duì)304不銹鋼的侵蝕過(guò)程中,當(dāng)Si含量由6wt.%增加到9wt.%時(shí),侵蝕速率和侵蝕層厚度降低,當(dāng)Si含量由9wt.%增加到12wt.%時(shí),侵蝕速率和侵蝕層厚度略有增加,當(dāng)Si含量由12wt.%增加到15wt.%時(shí),侵蝕速率和侵蝕層厚度顯著增加。在Al-12Si-15Cu合金熔體中添加2wt.%Mg元素后,侵蝕速率和侵蝕層厚度都降低。由試驗(yàn)結(jié)果及動(dòng)力學(xué)分析可知,Al-xSi-yCu-zMg合金熔體對(duì)304不銹鋼的侵蝕類型為擴(kuò)散侵蝕,侵蝕速率主要取決于Al元素的擴(kuò)散,Cu元素和Mg元素均未參與侵蝕反應(yīng)。侵蝕層是由與304不銹鋼相鄰的內(nèi)侵蝕層和與合金熔體相鄰的外侵蝕層兩部組成的。內(nèi)侵蝕層主要由Al95Fe4Cr相組成,呈條帶狀,比較致密且顯微硬度高于外侵蝕層;當(dāng)Si元素含量低且侵蝕時(shí)間短時(shí),外侵蝕層主要由Fe2Al5相組成,Si填充Fe2Al5相的空位,阻礙了元素?cái)U(kuò)散,當(dāng)Si元素含量高且侵蝕時(shí)間長(zhǎng)時(shí),外侵蝕層主要由FexSiyAlz金屬間化合物、FeAl相和Al13Fe4相組成,FexSiyAlz生長(zhǎng)速率低且可阻擋元素的擴(kuò)散,從而降低侵蝕速率。在侵蝕過(guò)程中,與鋁合金熔體相鄰的外侵蝕層會(huì)因空洞聚集而變得疏松甚至開裂,鋁合金熔體進(jìn)入這些孔隙中,使得侵蝕層局部脫落,脫落塊最終破裂成更細(xì)的小片并完全溶于鋁合金熔體中。此外,Cr元素以金屬間化合物Al95Fe4Cr的形式存在,也可阻礙元素的擴(kuò)散,從而起到降低侵蝕速率的作用。
[Abstract]:The successful application of phase change energy storage technology is not only related to the thermal properties of energy storage materials, but also to the compatibility of energy storage materials melt and container materials.It has been shown that the phase change energy storage aluminum alloy has excellent thermal properties and has a broad application prospect in high temperature energy storage such as solar thermal power generation. However, it corrodes the surface of iron based containers seriously in high temperature liquid environment.It restricts its further development and application.In order to solve the above problems, eight kinds of alloys Al-12Si-xCuLi Al-xSi-10Cu and Al-12Si-15Cu-2Mg were selected as energy storage materials, and 304 stainless steel was used as container material to carry out erosion tests. The corrosion tests were carried out at different temperatures.The corrosion behavior of molten energy storage aluminum alloy to 304 stainless steel under the condition of time and component elements such as Cu-Si and Mg. combined with XRD analysis, metallographic structure analysis and EDS analysis revealed the corrosion mechanism of the molten energy storage aluminum alloy to 304 stainless steel.The experimental and theoretical basis is provided for reducing the erosivity of phase change energy storage aluminum alloy melt.For the eight alloys studied in this paper, when the erosion time is 24 h and the erosion temperature ranges from 580 鈩，

本文編號(hào)：1767995