【摘要】：隨著航天工業(yè)的快速發(fā)展,對(duì)于超高聲速飛行器具有迫切的需求。尋找在高溫下服役具有優(yōu)異性能的輕質(zhì)金屬材料是解決航空飛行器瓶頸問題的有效手段。NiAl金屬間化合物具有優(yōu)異的高溫性能和較低的密度,被認(rèn)為是最有前景的高溫結(jié)構(gòu)材料之一。但是,差的室溫塑性阻止了NiAl金屬間化合物的大規(guī)模應(yīng)用。塑性熱成形是實(shí)現(xiàn)其室溫強(qiáng)度和塑性協(xié)同提升的最有效方法之一。但是由于變形參數(shù)與微觀組織密切相關(guān)(即與性能密切相關(guān)),因此建立變形參數(shù)與微觀組織的關(guān)系非常重要。并且,變形誘導(dǎo)織構(gòu)對(duì)于構(gòu)件成形性能會(huì)產(chǎn)生顯著影響。因此,為了獲得具有理想微觀組織的構(gòu)件,需要考慮材料變形過程中產(chǎn)生的織構(gòu)。本文采用Ni和Al元素粉末作為初始材料,基于Al-Ni二元相圖制定出熱壓反應(yīng)燒結(jié)工藝曲線。通過熱壓燒結(jié)工藝制備塊狀NiAl材料。在變形溫度區(qū)間1100~1300℃,應(yīng)變速率區(qū)間1×10-3~1s-1進(jìn)行Gleeble高溫壓縮模擬實(shí)驗(yàn)。通過分析單向壓縮變形材料的力學(xué)響應(yīng)確定NiAl的高溫變形行為,并且構(gòu)造Arrhenius型本構(gòu)方程。采用Zenner-Hollomon參數(shù)驗(yàn)證所建立本構(gòu)方程的有效性。此外,通過原位拉伸實(shí)驗(yàn)進(jìn)一步了解NiAl材料的高溫變形行為。原位拉伸實(shí)驗(yàn)結(jié)果揭示了應(yīng)變速率改變時(shí)材料的力學(xué)響應(yīng),說(shuō)明了材料良好高溫塑性的原因�；诟邷刈冃涡袨�,根據(jù)動(dòng)態(tài)材料模型構(gòu)造了熱加工圖。通過熱加工圖確定了理想的熱加工窗口。根據(jù)熱加工圖優(yōu)化的熱加工窗口進(jìn)行了高溫鍛造,在高溫鍛造后,NiAl延伸率顯著上升。此外,高溫拉伸材料斷裂形貌分析揭示在高溫拉伸,應(yīng)變速率為10-3s-1時(shí),高溫鍛造后斷裂模式由脆性沿晶斷裂向塑性斷裂轉(zhuǎn)變。而應(yīng)變速率為10~(-2)s~(-1)時(shí),高溫鍛造后斷裂模式由脆性解理斷裂向塑性斷裂轉(zhuǎn)變。室溫拉伸斷口在材料高溫鍛造后由脆性穿晶斷裂向脆性解理斷裂和塑性斷裂的混合模式轉(zhuǎn)變。通過晶界形貌、晶粒取向差梯度和GOS值表征了微觀組織演變過程。結(jié)果顯示在高應(yīng)變速率,中等變形溫度下,軟化過程主要是連續(xù)動(dòng)態(tài)再結(jié)晶和非連續(xù)動(dòng)態(tài)再結(jié)晶的混合模式。在高變形溫度,中等應(yīng)變速率條件下,軟化過程主要是非連續(xù)動(dòng)態(tài)再結(jié)晶。并且發(fā)現(xiàn),由于連續(xù)亞晶轉(zhuǎn)動(dòng),連續(xù)動(dòng)態(tài)再結(jié)晶會(huì)導(dǎo)致材料織構(gòu)強(qiáng)度上升,而由于動(dòng)態(tài)再結(jié)晶晶粒替代初始形變晶粒,非連續(xù)動(dòng)態(tài)再結(jié)晶會(huì)導(dǎo)致材料織構(gòu)強(qiáng)度下降。初始熱壓燒結(jié)產(chǎn)物具有弱{111}uvw織構(gòu)。在1100℃/10~(-2)s~(-1)條件下進(jìn)行高溫變形,織構(gòu)主要由{110}111和{112}111組分構(gòu)成。
[Abstract]:With the rapid development of aerospace industry, there is an urgent need for UHV. Finding light metal materials with excellent performance at high temperature is an effective way to solve the bottleneck problem of aeronautical aircraft. NiAl intermetallic compounds have excellent high temperature performance and low density. It is considered to be one of the most promising high temperature structural materials. However, poor room temperature plasticity prevents large-scale applications of NiAl intermetallics. Plastic hot forming is one of the most effective methods to realize the synergistic enhancement of room temperature strength and plasticity. However, because deformation parameters are closely related to microstructure (that is, closely related to properties), it is very important to establish the relationship between deformation parameters and microstructure. In addition, deformation-induced textures have a significant effect on the formability of the components. Therefore, in order to obtain the components with ideal microstructure, the texture produced in the process of material deformation should be considered. In this paper, Ni and Al powders are used as the initial materials, and the hot pressing reaction sintering process curves are worked out based on the binary phase diagram of Al-Ni. Bulk NiAl materials were prepared by hot pressing sintering process. The Gleeble high temperature compression simulation experiment was carried out in the deformation temperature range of 1100 鈩，

本文編號(hào)：2280669