【摘要】：金屬薄板微成形工藝以其成形工藝簡單、成本低、高效、節(jié)能等一系列優(yōu)點而在制造領(lǐng)域內(nèi)受到廣泛的關(guān)注。為探究金屬薄板在成形過程中的力學(xué)性能,國內(nèi)外很多學(xué)者對其進(jìn)行了相關(guān)研究。在超聲拉伸方面,本文探究了T2紫銅薄板在超聲振動下的力學(xué)性能參數(shù);在金屬薄板微沖壓成形方面,本課題組提出了瞬態(tài)粘性介質(zhì)金屬薄板超聲微成形方法,通過金屬薄板超聲微脹形實驗,研究了該成形工藝中,超聲頭主壓力、超聲振幅及超聲加載時間對超聲氣膜效應(yīng)中氣膜厚度的影響。這些對金屬薄板微成形理論的進(jìn)一步研究具有重要的意義。本論文的主要研究工作及相關(guān)結(jié)論如下:(1)探究了T2紫銅薄板在不同退火溫度下的厚度/晶粒尺寸比關(guān)系。實驗結(jié)果表明:當(dāng)紫銅薄板的厚度減小到一定程度時,晶粒尺寸受薄板厚度變化的影響較大。在相同熱處理溫度下,隨著紫銅薄板厚度的增加,試樣晶粒尺寸也隨著增加,厚度/晶粒尺寸比也隨著增加;對于同一厚度紫銅薄板而言,隨著熱處理溫度的增加,晶粒尺寸也隨著增加,厚度/晶粒尺寸比隨著溫度的增加而減小,當(dāng)熱處理溫度達(dá)到600℃以后,厚度/晶粒尺寸比減小的趨勢逐漸趨于平緩。(2)研究了T2紫銅薄板在超聲拉伸條件下的相關(guān)力學(xué)性能參數(shù)。研究結(jié)果表明,當(dāng)厚度/晶粒尺寸比小于1時,隨著厚度/晶粒尺寸比的減小,屈服強度的增幅逐漸增加;變形抗力也隨著厚度/晶粒尺寸比的減小而降低。在超聲作用下,與未進(jìn)行退火處理的紫銅薄板相比,經(jīng)退火處理后的T2紫銅薄板,其屈服強度、抗拉強度及延伸率均出現(xiàn)了不同程度的降低,即表現(xiàn)出明顯的“軟化效應(yīng)”。(3)在瞬態(tài)粘性介質(zhì)金屬薄板超聲微成形工藝中,超聲頭主壓力對氣膜的影響呈負(fù)相關(guān)性,即隨著超聲頭主壓力的增加,氣膜的厚度呈降低趨勢。超聲振幅對氣膜厚度的影響呈現(xiàn)出先減后增的規(guī)律。隨著超聲加載時間的增加,氣膜厚度呈振蕩遞減的趨勢。對于厚度/晶粒尺寸比為1.1的T2紫銅薄板(厚度為30μm,熱處理溫度為600℃),對其進(jìn)行微脹形實驗,當(dāng)超聲頭主壓力為3.8MPa、超聲振幅為36.54μm、超聲加載時間為1.2s時,能夠?qū)饽さ暮穸瓤刂圃?.8-2.2μm之間。
[Abstract]:Metal sheet microforming process has attracted wide attention in manufacturing field because of its simple forming process, low cost, high efficiency, energy saving and so on. In order to study the mechanical properties of sheet metal in forming process, many scholars at home and abroad have studied it. In the aspect of ultrasonic drawing, the mechanical properties of T2 copper sheet under ultrasonic vibration are studied, and the ultrasonic microforming method of transient viscous medium metal sheet is proposed in this paper. The effects of the main pressure of ultrasonic head, ultrasonic amplitude and ultrasonic loading time on the film thickness in ultrasonic film effect were studied by ultrasonic microbulging test of metal sheet. These are of great significance to the further study of metal sheet microforming theory. The main research work and related conclusions are as follows: (1) the relationship between thickness and grain size ratio of T2 red copper sheet at different annealing temperatures has been investigated. The experimental results show that when the thickness of copper sheet decreases to a certain extent, the grain size is greatly affected by the thickness of the plate. At the same heat treatment temperature, with the increase of the thickness of the copper sheet, the grain size of the sample also increases, and the thickness / grain size ratio increases with the increase of the heat treatment temperature. With the increase of grain size, the thickness / grain size ratio decreases with the increase of temperature, and when the heat treatment temperature reaches 600 鈩，

本文編號：2197272