高能電脈沖作用下變形鎂合金的微觀組織及力學(xué)性能研究
發(fā)布時間：2018-08-02 12:13
【摘要】：在當(dāng)前能源危機(jī)和人類需求多樣化的背景下,鎂合金作為最輕的金屬結(jié)構(gòu)材料和其豐富的儲量而備受關(guān)注,但是由于鎂合金在室溫下塑性較差,而且其強(qiáng)度也較低,限制了它的推廣應(yīng)用。根據(jù)經(jīng)典金屬學(xué)原理可知,晶粒細(xì)化不僅可以改善材料的塑性,同時可以提高材料的強(qiáng)度,因此,本論文試圖采用晶粒細(xì)化法改善鎂合金的性能。電脈沖處理是一種新興的材料處理方法,其具有輸入能量大,效率高等特點(diǎn)。近年來,應(yīng)用電脈沖處理細(xì)化材料的微觀組織已取得了良好的效果。因此,本文應(yīng)用高能電脈沖處理軋制變形態(tài)的AZ31B鎂合金,首先,通過控制室溫軋制變形量、脈沖寬度、脈沖時間等實(shí)驗(yàn)參數(shù),利用正交試驗(yàn)的方法,研究電脈沖處理參數(shù)對微觀組織(再結(jié)晶分?jǐn)?shù)、平均晶粒尺寸)的影響,并測定力學(xué)性能。其次,通過控制脈沖寬度,考察試樣的再結(jié)晶組織轉(zhuǎn)變過程,并從理論上分析電脈沖處理的熱效應(yīng)和非熱效應(yīng)對變形鎂合金再結(jié)晶晶粒形核與長大以及再結(jié)晶機(jī)理的影響。再結(jié)晶分?jǐn)?shù)分析表明,軋制變形量和脈沖寬度對再結(jié)晶分?jǐn)?shù)的影響較大,再結(jié)晶分?jǐn)?shù)隨著二者的增大明顯升高,而脈沖時間對再結(jié)晶分?jǐn)?shù)的影響相對較小;平均晶粒尺寸分析表明,軋制變形量對平均晶粒尺寸影響較大,脈沖寬度和脈沖時間對其影響相對較小;熱效應(yīng)分析表明,試樣表面溫度受脈沖寬度和軋制變形量的影響較大,隨著脈沖寬度和軋制變形量的升高,試樣表面溫度急劇上升,而受脈沖時間的影響相對較小。通過分析選出的最優(yōu)參數(shù)為室溫軋制變形量38%、脈沖寬度70μs、脈沖時間10 min,在此條件下處理試樣,其晶粒尺寸由原始材料的140μm細(xì)化至6.8μm,極大的改善了微觀組織。力學(xué)性能測試表明,38%室溫軋制變形量試樣由于變形量過大而導(dǎo)致的內(nèi)部微裂紋嚴(yán)重弱化了其力學(xué)性能,但是次優(yōu)參數(shù)室溫軋制變形量30%、脈沖寬度70μs、脈沖時間10 min試樣的性能改善也非常明顯,抗拉強(qiáng)度提升至341 MPa,伸長率達(dá)到了11.6%。組織演變分析表明,隨著脈沖寬度的增大,變形組織逐漸發(fā)生再結(jié)晶,且再結(jié)晶轉(zhuǎn)變過程為:孿晶再結(jié)晶、孿晶和晶界再結(jié)晶、整體再結(jié)晶、晶粒長大。再結(jié)晶機(jī)理分析表明,電脈沖處理是通過熱效應(yīng)與非熱效應(yīng)共同作用促進(jìn)再結(jié)晶,且非熱效應(yīng)是促進(jìn)再結(jié)晶的主要原因,非熱效應(yīng)降低了再結(jié)晶形核勢壘,降低了原子擴(kuò)散激活能,提高再結(jié)晶形核率,進(jìn)而加速了再結(jié)晶。
[Abstract]:Under the background of the current energy crisis and the diversification of human needs, magnesium alloys, as the lightest metal structural materials and their abundant reserves, have attracted much attention. However, the plasticity of magnesium alloys at room temperature is poor, and the strength of magnesium alloys is also low. It limits its popularization and application. According to the classical metallography principle, grain refinement can not only improve the plasticity of the material, but also improve the strength of the material. Therefore, this paper attempts to improve the properties of magnesium alloy by grain refinement method. Electrical pulse processing is a new material processing method, which has the characteristics of large input energy and high efficiency. In recent years, the application of electric pulse to the treatment of fine material microstructure has achieved good results. Therefore, in this paper, high energy electric pulse is used to treat AZ31B magnesium alloy with variable shape. Firstly, by controlling the experimental parameters of room temperature rolling deformation, pulse width and pulse time, the orthogonal test method is used. The effect of electrical pulse processing parameters on microstructure (recrystallization fraction, average grain size) and mechanical properties were studied. Secondly, the process of recrystallization microstructure transformation of wrought magnesium alloy was investigated by controlling the pulse width, and the effects of thermal and non-thermal effects on the nucleation and growth of recrystallized grain and the mechanism of recrystallization of wrought magnesium alloy were analyzed theoretically. The recrystallization fraction analysis shows that the rolling deformation and pulse width have great influence on the recrystallization fraction, and the recrystallization fraction increases obviously with the increase of the recrystallization fraction, while the effect of pulse time on the recrystallization fraction is relatively small. The average grain size analysis shows that the rolling deformation has a great influence on the average grain size, while the pulse width and pulse time have relatively little effect on the average grain size, and the thermal effect analysis shows that the surface temperature of the sample is greatly affected by the pulse width and the rolling deformation. With the increase of pulse width and rolling deformation, the surface temperature of the sample increases sharply, but the influence of pulse time is relatively small. The optimum parameters are as follows: room temperature rolling deformation 38, pulse width 70 渭 s, pulse time 10 min. Under these conditions, the grain size of the sample is refined from 140 渭 m to 6.8 渭 m, which greatly improves the microstructure. The results of mechanical properties test show that the internal microcracks of 38% room temperature rolling specimens due to excessive deformation seriously weaken their mechanical properties. However, the mechanical properties of the suboptimal parameters, such as room temperature rolling deformation 30 and pulse width 70 渭 s, pulse time 10 min, were also improved obviously. The tensile strength was raised to 341 MPA, and the elongation reached 11.6 MPA. The microstructure evolution analysis shows that recrystallization occurs gradually with the increase of pulse width, and the recrystallization process is twinning recrystallization, twin recrystallization and grain boundary recrystallization, whole recrystallization and grain growth. The analysis of recrystallization mechanism shows that electrical pulse treatment promotes recrystallization through the interaction of thermal effect and non-thermal effect, and non-thermal effect is the main reason for promoting recrystallization, and non-thermal effect reduces the nucleation barrier of recrystallization. The activation energy of atomic diffusion is reduced, the nucleation rate of recrystallization is increased, and the recrystallization is accelerated.
【學(xué)位授予單位】：太原理工大學(xué)
【學(xué)位級別】：碩士
【學(xué)位授予年份】：2017
【分類號】：TG146.22
本文編號：2159401
[Abstract]:Under the background of the current energy crisis and the diversification of human needs, magnesium alloys, as the lightest metal structural materials and their abundant reserves, have attracted much attention. However, the plasticity of magnesium alloys at room temperature is poor, and the strength of magnesium alloys is also low. It limits its popularization and application. According to the classical metallography principle, grain refinement can not only improve the plasticity of the material, but also improve the strength of the material. Therefore, this paper attempts to improve the properties of magnesium alloy by grain refinement method. Electrical pulse processing is a new material processing method, which has the characteristics of large input energy and high efficiency. In recent years, the application of electric pulse to the treatment of fine material microstructure has achieved good results. Therefore, in this paper, high energy electric pulse is used to treat AZ31B magnesium alloy with variable shape. Firstly, by controlling the experimental parameters of room temperature rolling deformation, pulse width and pulse time, the orthogonal test method is used. The effect of electrical pulse processing parameters on microstructure (recrystallization fraction, average grain size) and mechanical properties were studied. Secondly, the process of recrystallization microstructure transformation of wrought magnesium alloy was investigated by controlling the pulse width, and the effects of thermal and non-thermal effects on the nucleation and growth of recrystallized grain and the mechanism of recrystallization of wrought magnesium alloy were analyzed theoretically. The recrystallization fraction analysis shows that the rolling deformation and pulse width have great influence on the recrystallization fraction, and the recrystallization fraction increases obviously with the increase of the recrystallization fraction, while the effect of pulse time on the recrystallization fraction is relatively small. The average grain size analysis shows that the rolling deformation has a great influence on the average grain size, while the pulse width and pulse time have relatively little effect on the average grain size, and the thermal effect analysis shows that the surface temperature of the sample is greatly affected by the pulse width and the rolling deformation. With the increase of pulse width and rolling deformation, the surface temperature of the sample increases sharply, but the influence of pulse time is relatively small. The optimum parameters are as follows: room temperature rolling deformation 38, pulse width 70 渭 s, pulse time 10 min. Under these conditions, the grain size of the sample is refined from 140 渭 m to 6.8 渭 m, which greatly improves the microstructure. The results of mechanical properties test show that the internal microcracks of 38% room temperature rolling specimens due to excessive deformation seriously weaken their mechanical properties. However, the mechanical properties of the suboptimal parameters, such as room temperature rolling deformation 30 and pulse width 70 渭 s, pulse time 10 min, were also improved obviously. The tensile strength was raised to 341 MPA, and the elongation reached 11.6 MPA. The microstructure evolution analysis shows that recrystallization occurs gradually with the increase of pulse width, and the recrystallization process is twinning recrystallization, twin recrystallization and grain boundary recrystallization, whole recrystallization and grain growth. The analysis of recrystallization mechanism shows that electrical pulse treatment promotes recrystallization through the interaction of thermal effect and non-thermal effect, and non-thermal effect is the main reason for promoting recrystallization, and non-thermal effect reduces the nucleation barrier of recrystallization. The activation energy of atomic diffusion is reduced, the nucleation rate of recrystallization is increased, and the recrystallization is accelerated.
【學(xué)位授予單位】：太原理工大學(xué)
【學(xué)位級別】：碩士
【學(xué)位授予年份】：2017
【分類號】：TG146.22
【參考文獻(xiàn)】
相關(guān)期刊論文 前10條
1 周亞軍;張發(fā)廳;劉建秀;;燒結(jié)工藝對粉末冶金法制備鎂合金摩擦磨損性能的影響[J];鑄造技術(shù);2013年12期
2 楊偉東;樊建鋒;張金玲;張艷萍;謝中柱;許并社;;燒結(jié)溫度對粉末冶金AZ91鎂合金組織及硬度的影響[J];材料熱處理學(xué)報;2013年01期
3 曾真;信運(yùn)昌;王茂銀;劉慶;;孿晶類型對AZ31鎂合金靜態(tài)再結(jié)晶的影響[J];材料熱處理學(xué)報;2012年08期
4 袁付慶;張靜;方超;;稀土元素對鎂合金晶粒細(xì)化的研究[J];熱加工工藝;2012年02期
5 羅晉如;劉慶;劉偉;Godfrey Andrew;;AZ31鎂合金板軋制過程中的{1011)-{1012)雙孿生對板材顯微組織、織構(gòu)、力學(xué)性能的影響[J];金屬學(xué)報;2011年12期
6 彭友霖;周麗麗;周艷紅;;鎂合金作為生物醫(yī)用植入材料的臨床應(yīng)用[J];中國組織工程研究與臨床康復(fù);2011年42期
7 劉瑞江;張業(yè)旺;聞崇煒;湯建;;正交試驗(yàn)設(shè)計和分析方法研究[J];實(shí)驗(yàn)技術(shù)與管理;2010年09期
8 張丁非;方霖;劉郭平;戴慶偉;;鎂合金板材軋制技術(shù)與工藝的研究進(jìn)展[J];兵器材料科學(xué)與工程;2010年05期
9 李蕭;楊平;孟利;崔鳳娥;;AZ31鎂合金中拉伸孿晶靜態(tài)再結(jié)晶的分析[J];金屬學(xué)報;2010年02期
10 彭穎紅;唐偉琴;張少睿;李大永;;基于滑移/孿生耦合模型的鎂合金多晶體塑性成形分析[J];塑性工程學(xué)報;2009年05期
相關(guān)重要報紙文章 前1條
1 楊晨;;實(shí)現(xiàn)鎂合金在中國軍工領(lǐng)域的首次應(yīng)用[N];中國有色金屬報;2016年
，本文編號：2159401
本文鏈接：http://sikaile.net/shoufeilunwen/boshibiyelunwen/2159401.html
最近更新
教材專著
