本文關(guān)鍵詞： TA2鈦合金 超聲表面滾壓 等離子滲氮 三體摩擦　出處：《中國(guó)地質(zhì)大學(xué)(北京)》2017年碩士論文　論文類(lèi)型：學(xué)位論文

【摘要】：TA2鈦合金作為一種輕質(zhì)結(jié)構(gòu)材料被廣泛應(yīng)用于航天器件、特殊地質(zhì)鉆探等領(lǐng)域,但其合金含量少、硬度低、不耐磨,易產(chǎn)生粘著磨損,因此必須對(duì)其進(jìn)行表面強(qiáng)化。本研究旨在探究模擬月壤顆粒對(duì)TA2鈦合金表面第三體形成的影響及TA2鈦合金的表面強(qiáng)化及抗磨機(jī)制,對(duì)鈦合金在月壤取樣工程中的應(yīng)用具有重要意義。本研究運(yùn)用超聲表面滾壓(USRP)+離子滲氮的復(fù)合強(qiáng)化技術(shù),選用750℃氮化,USRP+750℃氮化,850℃氮化,USRP+850℃氮化對(duì)TA2進(jìn)行表面強(qiáng)化,運(yùn)用顯微硬度、光學(xué)顯微、XRD、SEM、EDS等微觀分析表征了所制備的鈦合金樣品;并創(chuàng)造性地添加模擬月壤顆粒作為外源第三體,研究了鈦合金的三體摩擦學(xué)性能。研究結(jié)果為:(1)“USRP+離子滲氮”的復(fù)合強(qiáng)化處理能有效提高TA2的力學(xué)及摩擦學(xué)性能。USRP預(yù)處理能夠促進(jìn)離子滲氮,提高強(qiáng)化層厚度和表面硬度,USRP+850℃離子氮化處理后TA2鈦合金的性能改善最明顯且硬度提升最大,至1097HV0.05。同時(shí)USRP處理能夠減小樣品氮化后的表面粗糙度,使氮化鈦合金的表面性能有所改善,摩擦系數(shù)減小。(2)在干摩擦條件下,模擬月壤顆粒在鈦合金表面可形成連續(xù)分布的第三體,對(duì)摩擦學(xué)性能有決定性影響。第三體起到隔離摩擦副的作用,顆粒的微滾動(dòng)減小了摩擦阻力,同時(shí)使摩擦過(guò)程更穩(wěn)定,使鈦合金的摩擦系數(shù)減小。(3)在三體摩擦學(xué)體系中,硬質(zhì)第三體磨粒會(huì)對(duì)低硬度鈦合金產(chǎn)生明顯犁削作用,顆粒的“釘扎作用”會(huì)造成二次磨損,增大了鈦合金材料的磨損率。750℃氮化鈦合金的主要磨損機(jī)制為犁削磨損;第三體磨粒在磨痕處的聚集會(huì)加劇表面的應(yīng)力集中,使850℃氮化鈦合金萌生更多疲勞裂紋從而產(chǎn)生疲勞磨損。(4)不同粒徑的模擬月壤顆粒對(duì)氮化鈦合金的摩擦學(xué)性能有重要影響。大粒徑(200-991μm)模擬月壤顆粒容易形成強(qiáng)力鏈,增大了摩擦阻力、加劇了載荷分布的不均勻性,使摩擦系數(shù)及波動(dòng)增大,也更容易產(chǎn)生顯微切削形成嚴(yán)重磨粒磨損。小粒徑顆粒在摩擦過(guò)程中使應(yīng)力分布更均勻,摩擦系數(shù)減小,但此時(shí)加劇了高硬度氮化鈦合金的疲勞破壞,造成表面疲勞磨損。
[Abstract]:As a light structure material, TA2 titanium alloy is widely used in spacecrafts, special geological drilling and other fields, but its alloy content is low, hardness is low, wear resistance is not good, and adhesive wear is easy to occur. The purpose of this study was to investigate the effects of simulated lunar soil particles on the formation of the third body on the surface of TA2 titanium alloy and the mechanism of surface strengthening and antiwear of TA2 titanium alloy. It is of great significance for the application of titanium alloy in lunar soil sampling engineering. In this study, the surface strengthening of TA2 was carried out by using the composite strengthening technology of ultrasonic surface rolling pressing (USRP) ion nitriding. The titanium alloy samples were characterized by microhardness and optical microanalysis, and the simulated lunar soil particles were creatively added as the external third body. The tribological properties of titanium alloy were studied. The results show that the compound strengthening treatment of "USRP ion nitriding" can effectively improve the mechanical and tribological properties of TA2. The properties and hardness of TA2 titanium alloy were improved most obviously by increasing the thickness of strengthening layer and surface hardness after ion nitridation at 850 鈩，

本文編號(hào)：1541806