【摘要】：鈦合金因具有比強(qiáng)度高、耐腐蝕、耐熱性能好、耐低溫性能好、彈性模量低等優(yōu)良特性而廣泛應(yīng)用到航空航天、航海及民用設(shè)施領(lǐng)域，因此利用相輔助形核進(jìn)行鈦合金組織性能優(yōu)化的研究具有重要的理論意義與經(jīng)濟(jì)價(jià)值。本論文以Ti-23V、Ti-7Fe、Ti-14V合金為研究體系，采用常規(guī)的合金制備手段和XRD衍射儀、掃描電鏡、光學(xué)顯微鏡、硬度儀、萬(wàn)能拉伸機(jī)等儀器，，研究鈦合金經(jīng)雙步時(shí)效熱處理時(shí)相輔助形核對(duì)組織性能的影響。研究結(jié)果如下： （1）研究了Ti-23V合金第一步時(shí)效溫度對(duì)雙步時(shí)效處理合金組織性能的影響。第一步時(shí)效溫度過低或過高，合金均未獲得理想的輔助形核效果；而當(dāng)?shù)谝徊綍r(shí)效溫度比較適中（如350℃）時(shí)，合金雙步時(shí)效后組織呈現(xiàn)大量超細(xì)、彌散的晶內(nèi)相且無(wú)晶界相（GB）和無(wú)相析出區(qū)域（PFZs），合金具有良好的塑性及抗拉強(qiáng)度，合金斷口形貌是具有韌窩的韌性斷裂。 （2）研究了Ti-23V合金400℃下第一步時(shí)效時(shí)間對(duì)雙步時(shí)效處理合金組織性能的影響。第一步時(shí)效時(shí)間較短時(shí)，合金強(qiáng)度較高，但塑性降低；而第一步時(shí)效時(shí)間較長(zhǎng)時(shí)，合金強(qiáng)度降低，但塑性升高；但第一步時(shí)效時(shí)間過長(zhǎng)時(shí)合金強(qiáng)度及塑性均顯著下降。 （3）研究了Ti-7Fe合金第一步時(shí)效溫度對(duì)雙步時(shí)效處理合金組織性能的影響。未經(jīng)均勻化處理及經(jīng)均勻化處理時(shí)，合金中輔助相形核都僅能在犧牲塑性的基礎(chǔ)上改善合金的強(qiáng)度。未經(jīng)均勻化處理試樣為脆性斷裂，而經(jīng)均勻化處理試樣為脆性斷裂和韌性斷裂混合型斷裂。 （4）研究了Ti-7Fe合金400℃下第一步時(shí)效時(shí)間對(duì)雙步時(shí)效處理合金組織性能的影響。隨著第一步時(shí)效時(shí)間的變化，合金的強(qiáng)度能夠提高，但是合金的塑性仍是隨著強(qiáng)度的升高而減低。合金的斷口形貌顯現(xiàn)明顯的脆性斷裂。 （5）研究了Ti-14V合金ω相輔助形核對(duì)組織性能的影響。在400℃時(shí)效時(shí)，Ti-14V合金的抗拉強(qiáng)度隨著時(shí)效時(shí)間延長(zhǎng)呈現(xiàn)先增加后下降再升高的趨勢(shì)，而合金的塑性變化趨勢(shì)恰與抗拉強(qiáng)度變化相反。
[Abstract]:Titanium alloys are widely used in aerospace, navigation and civil facilities because of their high specific strength, corrosion resistance, good heat resistance, good low temperature resistance and low elastic modulus. Therefore, it is of great theoretical significance and economic value to optimize the microstructure and properties of titanium alloys by phase-assisted nucleation. In this paper, Ti-23V,Ti-7Fe,Ti-14V alloy was used as the research system, using conventional alloy preparation means and XRD diffractometer, scanning electron microscope, optical microscope, hardness meter, universal drawing machine and so on. The effect of phase auxiliary shape on microstructure and properties of titanium alloy during two-step aging heat treatment was studied. The results are as follows: (1) the effect of the first step aging temperature of Ti-23V alloy on the microstructure and properties of the alloy treated by two-step aging was studied. When the first step aging temperature is too low or too high, the alloy does not obtain the ideal auxiliary nucleation effect. When the first step aging temperature is moderate (such as 350 鈩

本文編號(hào)：2485017