本文選題：AZ31鎂合金 + LSP��； 參考：《河南科技大學(xué)》2015年碩士論文

【摘要】：鎂合金是輕質(zhì)的結(jié)構(gòu)金屬材料,具有比強(qiáng)度和比剛度高、阻尼性能好、導(dǎo)熱性好、屏蔽性好、易回收等一系列的優(yōu)良性能,有著廣闊的應(yīng)用前景,目前已廣泛應(yīng)用于航空航天業(yè)、汽車工業(yè)、電子制造等領(lǐng)域。但是鎂合金在力學(xué)性能上的局限性及耐腐蝕性能差等嚴(yán)重制約了其廣泛的應(yīng)用。本文利用激光沖擊強(qiáng)化(Laser Shock Processing,LSP)技術(shù)研究了AZ31鎂合金在高速?zèng)_擊作用下的組織和性能變化,同時(shí)也分析了退火處理對(duì)激光沖擊AZ31鎂合金組織和性能的影響,從而提高其綜合性能及使用價(jià)值,具有理論和現(xiàn)實(shí)意義。對(duì)時(shí)效處理后的鎂合金進(jìn)行激光沖擊強(qiáng)化處理。激光沖擊處理后AZ31鎂合金試樣的表層微觀結(jié)構(gòu)以高密度位錯(cuò)纏結(jié)為主,表層硬度為140HV,較沖擊前提高了127%;試樣的抗拉強(qiáng)度為305MPa,提高了21%;斷裂延伸率提高了16%,激光沖擊處理后材料的強(qiáng)度與韌性均得到明顯提高且試樣的自腐蝕電位較沖擊前正移約880 mV,自腐蝕電流也明顯降低,耐蝕性能顯著提高。對(duì)激光沖擊處理后的AZ31鎂合金進(jìn)行不同時(shí)間和溫度的退火處理,經(jīng)過350℃×30min退火處理后,鎂合金的電極電位正移,自腐蝕電位達(dá)到-583mV,較沖擊前正移了992mV,較沖擊后正移了103mV,自腐蝕電流密度比沖擊后降低了兩個(gè)數(shù)量級(jí),耐蝕性能得到明顯提高;隨著退火溫度的升高及退火時(shí)間的延長,合金的硬度逐漸降低;在相同的退火時(shí)間(30min)條件下,抗拉強(qiáng)度及延伸率在200℃~350℃溫度區(qū)間內(nèi),隨著溫度的升高逐漸增加,在400℃退火后迅速降低;在相同的退火溫度(350℃)條件下,隨著時(shí)間的延長抗拉強(qiáng)度逐步降低,伸長率先略有增加然后降低;最佳的退火溫度及時(shí)間為350℃×30min,抗拉強(qiáng)度和斷裂延伸率分別達(dá)到342MPa及18%。不同的退火工藝對(duì)激光沖擊后合金的斷口形貌有明顯影響,在350℃×30min退火后斷口呈現(xiàn)一定的韌性特征。經(jīng)過適當(dāng)?shù)耐嘶鹛幚砗笤嚇颖韺泳Я５玫郊?xì)化,在350℃×30min退火處理后試樣局部形成納米晶。
[Abstract]:Magnesium alloy is a light structural metal material with high specific strength and stiffness, good damping property, good thermal conductivity, good shielding property, easy recovery and a series of excellent properties, so it has a broad application prospect. At present, it has been widely used in aerospace industry, automobile industry, electronic manufacturing and other fields. However, the limitation of mechanical properties and poor corrosion resistance of magnesium alloys restrict their wide application. In this paper, the microstructure and properties of AZ31 magnesium alloy under high speed impact were studied by laser shock hardening laser processing technique, and the effect of annealing on the microstructure and properties of AZ31 magnesium alloy was also analyzed. In order to improve its comprehensive performance and use value, it has theoretical and practical significance. The aging magnesium alloy was strengthened by laser impact. The microstructure of surface layer of AZ31 magnesium alloy treated by laser shock is mainly high density dislocation entanglement. The hardness of the surface layer is 140 HVV, which is 12775 higher than that before the impact, the tensile strength of the sample is 305 MPA, the tensile strength of the sample increases 21%, the elongation at break increases 16%, the strength and toughness of the material after laser shock treatment are obviously improved and the self-corrosion potential of the sample is higher than that of the impact. The forward shift is about 880mV, and the corrosion current decreases obviously. The corrosion resistance is greatly improved. AZ31 magnesium alloy after laser shock treatment was annealed at different time and temperature. After 350 鈩，

本文編號(hào)：2010932