周科朝， 賀躍輝， 劉 詠
(中南大學(xué) 粉末冶金國家重點(diǎn)實(shí)驗(yàn)室， 長沙 410083)
摘 要: 利用光學(xué)顯微鏡（OM）和TEM，研究了全層狀TiAl合金的層片間距的影響因素及與各因素的關(guān)系。 實(shí)驗(yàn)結(jié)果表明， 全層狀TiAl合金的層片間距與冷卻速度和合金中鋁含量有關(guān)， 層片間距與冷卻速度呈反比關(guān)系， 并隨著合金中鋁含量的增加而增加。 同時，以層片生長的臺階機(jī)制為基礎(chǔ)， 推導(dǎo)出了全層狀TiAl合金在連續(xù)冷卻過程中層片間距的數(shù)學(xué)表達(dá)式， 推導(dǎo)結(jié)果與實(shí)驗(yàn)結(jié)果相符。
關(guān)鍵字: TiAl合金； 層片間距； 冷卻速度； Al含量
HE Yue-hui, Liu Yong
（State Key Laboratory for Powder Metallurgy, Central South University, Changsha 410083, China）
Abstract:It is important to control the lamellar spacing of fully lamellar TiAl alloy for improving its mechanical properties. The factors affecting the lamellar spacing of fully lamellar TiAl alloy and the dependence of the lamellar spacing on the factors were investigated by means of OM and TEM. The results show that the lamellar spacing depends on cooling rate and Al content. The lamellar spacing is inversely proportional to cooling rate and increases with the increase of Al content. At the same time, a theoretical expression of the lamellar spacing of fully lamellar TiAl alloy during continuous cooling has been derived on the basis of the ledge mechanism of lamellae growth. The theoretical results are in agreement with the experimental findings.
Key words: TiAl; lamellar spacing; cooling rate; Al content
