TC11鈦合金具有比強(qiang)(qiang)度高、耐高溫、耐腐(fu)蝕和加工(gong)(gong)性良好等(deng)特點(dian)，常作為結構材(cai)料(liao)(liao)用(yong)于制造壓氣機盤、葉片等(deng)零部件，有著廣(guang)泛(fan)的(de)應用(yong)[1-4]。近年來，隨著技術(shu)(shu)水平的(de)不斷(duan)提(ti)高，對(dui)TC11鈦合(he)金(jin)的(de)需(xu)求逐(zhu)年提(ti)升(sheng)，同(tong)時(shi)(shi)也對(dui)TC11鈦合(he)金(jin)的(de)使用(yong)性能(neng)(neng)(neng)，尤其是綜(zong)合(he)力(li)學性能(neng)(neng)(neng)提(ti)出了(le)更高的(de)要求。為了(le)獲得綜(zong)合(he)力(li)學性能(neng)(neng)(neng)良好的(de)TC11鈦合(he)金(jin)，工(gong)(gong)業上(shang)常通過退火處(chu)理(li)、淬火時(shi)(shi)效處(chu)理(li)和形(xing)變熱(re)處(chu)理(li)等(deng)工(gong)(gong)藝來改善微(wei)觀組織結構[5-9]。白(bai)鷺等(deng)[10]對(dui)TC11進(jin)行(xing)了(le)700℃熱(re)旋(xuan)壓+時(shi)(shi)效處(chu)理(li)，研究表明，TC11的(de)抗拉(la)強(qiang)(qiang)度最大可達到1242MPa，與退火態的(de)TC11鈦合(he)金(jin)原(yuan)料(liao)(liao)相比，綜(zong)合(he)力(li)學性能(neng)(neng)(neng)得到了(le)顯(xian)著的(de)提(ti)升(sheng)。然而，這些方法存在工(gong)(gong)藝周(zhou)期長、工(gong)(gong)藝復雜等(deng)缺(que)點(dian)。因(yin)此，探索一種新的(de)熱(re)處(chu)理(li)技術(shu)(shu)，對(dui)提(ti)高鈦合(he)金(jin)的(de)綜(zong)合(he)力(li)學性能(neng)(neng)(neng)具有重要意義。

近年來研究(jiu)發現，在(zai)熱(re)(re)處(chu)理(li)過程中施加壓(ya)力可以促進(jin)新(xin)相(xiang)形核，細化晶粒尺寸，從而改(gai)善材料的(de)(de)微觀(guan)結構和(he)(he)(he)力學(xue)(xue)性(xing)能(neng)[11-15]。Gu等[16]對(dui)(dui)熔滲(shen)(shen)后(hou)的(de)(de)Cu-Cr合(he)金進(jin)行了(le)高(gao)壓(ya)熱(re)(re)處(chu)理(li)，結果表(biao)明，經(jing)(jing)過3GPa的(de)(de)高(gao)壓(ya)處(chu)理(li)后(hou)，Cu-Cr合(he)金的(de)(de)硬度(du)(du)和(he)(he)(he)壓(ya)縮屈(qu)服強(qiang)(qiang)度(du)(du)分別(bie)為134HB和(he)(he)(he)241MPa，比滲(shen)(shen)透態(tai)Cu-Cr合(he)金的(de)(de)分別(bie)提高(gao)了(le)11.67%和(he)(he)(he)19.31%。Wei等[17]研究(jiu)發現，在(zai)2GPa和(he)(he)(he)474K下處(chu)理(li)1h后(hou)，Al-Mg合(he)金的(de)(de)力學(xue)(xue)性(xing)能(neng)顯著改(gai)善，拉(la)伸強(qiang)(qiang)度(du)(du)達到467MPa，屈(qu)服強(qiang)(qiang)度(du)(du)達到245MPa，是常壓(ya)處(chu)理(li)的(de)(de)3倍。劉建強(qiang)(qiang)等[18]對(dui)(dui)TC6鈦合(he) 金進(jin)行了(le)2GPa高(gao)壓(ya)熱(re)(re)處(chu)理(li)，研究(jiu)發現，經(jing)(jing)2GPa高(gao)壓(ya)熱(re)(re)處(chu)理(li)后(hou)，TC6合(he)金的(de)(de)硬度(du)(du)為5.27GPa，彈性(xing)模量為131.36GPa，較(jiao)退火態(tai)的(de)(de)4.12GPa和(he)(he)(he)117.24GPa有了(le)較(jiao)大的(de)(de)提升。然(ran)而，現階段關于高(gao)壓(ya)熱(re)(re)處(chu)理(li)對(dui)(dui)TC11合(he)金微觀(guan)組(zu)(zu)織影響和(he)(he)(he)力學(xue)(xue)性(xing)能(neng)關系的(de)(de)研究(jiu)較(jiao)少。為此(ci)，本文將研究(jiu)高(gao)壓(ya)熱(re)(re)處(chu)理(li)對(dui)(dui)TC11鈦合(he)金微觀(guan)組(zu)(zu)織和(he)(he)(he)力學(xue)(xue)性(xing)能(neng)的(de)(de)影響規(gui)律。

1、實驗

選擇退火態的TC11鈦合金為(wei)研究(jiu)對象，其化(hua)學(xue)成分如(ru)表1所示(shi)。采用六面頂高壓(ya)設備對試(shi)(shi)(shi)樣尺寸為(wei)Φ6mm×10mm的退(tui)火(huo)態(tai)(tai)TC11鈦合(he)金(jin)試(shi)(shi)(shi)樣進(jin)(jin)行高壓(ya)熱(re)處理實驗，其工藝(yi)示(shi)意圖(tu)如(ru)圖(tu)1所示(shi)。高壓(ya)熱(re)處理工藝(yi)流程如(ru)下(xia)(xia)：分別在1、3、5GPa壓(ya)力(li)下(xia)(xia)，將退(tui)火(huo)態(tai)(tai)TC11鈦合(he)金(jin)試(shi)(shi)(shi)樣加熱(re)至(zhi)(zhi)1000℃并(bing)保持20min，然后斷電取(qu)出(chu)試(shi)(shi)(shi)樣，空(kong)冷至(zhi)(zhi)室溫。為(wei)了對比研究(jiu)，在常壓(ya)下(xia)(xia)對退(tui)火(huo)態(tai)(tai)TC11鈦合(he)金(jin)試(shi)(shi)(shi)樣進(jin)(jin)行熱(re)處理，其工藝(yi)過程為(wei)：在KL-12D箱式電阻爐(lu)中將試(shi)(shi)(shi)樣加熱(re)至(zhi)(zhi)1000℃并(bing)保持20min，然后取(qu)出(chu)試(shi)(shi)(shi)樣空(kong)冷至(zhi)(zhi)室溫。

采用納米力學測試儀（納米壓痕壓頭為曲率半徑150nm的Berkovich壓頭）對高壓熱處理和常壓熱處理的TC11鈦合金試樣的抗塑性變形能力進行測試，采用的外力載荷為3000μN，載荷保持時間為2min，載荷加載和卸載速率均為90μN/s。采用WDW3100型電子萬能實驗機和FM-ARS-9000型硬度計對實驗試樣的室溫抗壓強度和硬度進行測試。采用Gleeble-3800熱模擬實驗機測試400℃下試樣的抗壓強度，具體過程如下：以5℃/s的加熱速率升溫到400℃，然后在該溫度下保持3min，在變形速率為1s^?1條件下進行(xing)(xing)熱壓(ya)縮實(shi)驗。采用S-4800掃描電子顯微(wei)鏡（SEM）對試(shi)樣的顯微(wei)組織和(he)壓(ya)縮斷(duan)口(kou)進行(xing)(xing)分析(xi)。采用DMAX-RB型號X射線衍射儀（XRD）分析(xi)試(shi)樣物相組成，采用JEOL-2010透射電子顯微(wei)鏡（TEM）觀察試(shi)樣的微(wei)觀組織和(he)位(wei)錯密度。

2、結果與分析

2.1高壓熱處理后TC11鈦合金微觀組織

不(bu)(bu)同(tong)狀(zhuang)態下TC11鈦(tai)合(he)(he)金(jin)的(de)(de)顯微(wei)(wei)組(zu)(zu)織(zhi)如圖(tu)2所(suo)示。由圖(tu)2a可以(yi)(yi)看出，原始(shi)退火態TC11鈦(tai)合(he)(he)金(jin)試樣(yang)的(de)(de)微(wei)(wei)觀(guan)(guan)組(zu)(zu)織(zhi)由α相(xiang)(xiang)(xiang)(xiang)和晶間β相(xiang)(xiang)(xiang)(xiang)組(zu)(zu)成，其(qi)中α相(xiang)(xiang)(xiang)(xiang)為(wei)(wei)(wei)圖(tu)2a中的(de)(de)白色組(zu)(zu)織(zhi)，表現出不(bu)(bu)規則的(de)(de)塊(kuai)狀(zhuang)和條(tiao)(tiao)狀(zhuang)特(te)(te)征，β相(xiang)(xiang)(xiang)(xiang)為(wei)(wei)(wei)晶間黑(hei)色組(zu)(zu)織(zhi)。圖(tu)2b為(wei)(wei)(wei)經1000℃常(chang)壓退火處(chu)(chu)(chu)(chu)理(li)后(hou)(hou)的(de)(de)微(wei)(wei)觀(guan)(guan)組(zu)(zu)織(zhi)形貌(mao)，可以(yi)(yi)看到(dao)，組(zu)(zu)織(zhi)由條(tiao)(tiao)狀(zhuang)α相(xiang)(xiang)(xiang)(xiang)和晶間β組(zu)(zu)成。與原始(shi)退火態相(xiang)(xiang)(xiang)(xiang)比，圖(tu)2b中α相(xiang)(xiang)(xiang)(xiang)的(de)(de)特(te)(te)征形貌(mao)發生了(le)變化，由不(bu)(bu)規則的(de)(de)塊(kuai)狀(zhuang)全部轉化為(wei)(wei)(wei)條(tiao)(tiao)狀(zhuang)，經測(ce)量，常(chang)壓處(chu)(chu)(chu)(chu)理(li)后(hou)(hou)，α相(xiang)(xiang)(xiang)(xiang)板(ban)條(tiao)(tiao)束長(chang)度約為(wei)(wei)(wei)21.5μm，板(ban)條(tiao)(tiao)束寬(kuan)度約為(wei)(wei)(wei)3.45μm，如圖(tu)2c—e所(suo)示，經高壓熱(re)處(chu)(chu)(chu)(chu)理(li)后(hou)(hou)，組(zu)(zu)織(zhi)中的(de)(de)α相(xiang)(xiang)(xiang)(xiang)呈頸縮連接或局部斷開的(de)(de)細(xi)(xi)條(tiao)(tiao)狀(zhuang)，與常(chang)壓熱(re)處(chu)(chu)(chu)(chu)理(li)的(de)(de)試樣(yang)相(xiang)(xiang)(xiang)(xiang)比，經過高壓熱(re)處(chu)(chu)(chu)(chu)理(li)的(de)(de)TC11鈦(tai)合(he)(he)金(jin)組(zu)(zu)織(zhi)中的(de)(de)α相(xiang)(xiang)(xiang)(xiang)得到(dao)了(le)明顯細(xi)(xi)化，α相(xiang)(xiang)(xiang)(xiang)板(ban)條(tiao)(tiao)束長(chang)度為(wei)(wei)(wei)8~10μm，板(ban)條(tiao)(tiao)束寬(kuan)度為(wei)(wei)(wei)1.4~1.6μm。進一步分(fen)析1、3、5GPa壓力(li)(li)處(chu)(chu)(chu)(chu)理(li)試樣(yang)微(wei)(wei)觀(guan)(guan)組(zu)(zu)織(zhi)的(de)(de)差(cha)異，可以(yi)(yi)發現，隨著壓力(li)(li)的(de)(de)增大，合(he)(he)金(jin)的(de)(de)組(zu)(zu)織(zhi)特(te)(te)征變化不(bu)(bu)明顯，相(xiang)(xiang)(xiang)(xiang)比之下，3GPa壓力(li)(li)處(chu)(chu)(chu)(chu)理(li)后(hou)(hou)的(de)(de)組(zu)(zu)織(zhi)較細(xi)(xi)，α相(xiang)(xiang)(xiang)(xiang)板(ban)條(tiao)(tiao)束的(de)(de)長(chang)度約為(wei)(wei)(wei)8.25μm，寬(kuan)度約為(wei)(wei)(wei)1.45μm，因此，選擇3GPa壓力(li)(li)處(chu)(chu)(chu)(chu)理(li)試樣(yang)為(wei)(wei)(wei)代(dai)表，與常(chang)壓熱(re)處(chu)(chu)(chu)(chu)理(li)試樣(yang)進行對(dui)比分(fen)析。

以3GPa高(gao)壓(ya)(ya)(ya)(ya)(ya)熱(re)(re)(re)(re)處(chu)理(li)(li)(li)試(shi)樣和(he)常(chang)壓(ya)(ya)(ya)(ya)(ya)處(chu)理(li)(li)(li)試(shi)樣為(wei)(wei)例，進(jin)行(xing)TEM形(xing)貌對比分(fen)析，研(yan)究高(gao)壓(ya)(ya)(ya)(ya)(ya)熱(re)(re)(re)(re)處(chu)理(li)(li)(li)與(yu)(yu)常(chang)壓(ya)(ya)(ya)(ya)(ya)熱(re)(re)(re)(re)處(chu)理(li)(li)(li)對TC11鈦(tai)合(he)金顯(xian)微(wei)組(zu)(zu)織(zhi)(zhi)的(de)(de)影響。圖(tu)3a為(wei)(wei)常(chang)壓(ya)(ya)(ya)(ya)(ya)熱(re)(re)(re)(re)處(chu)理(li)(li)(li)TC11鈦(tai)合(he)金的(de)(de)TEM形(xing)貌，可(ke)(ke)以看出，α相(xiang)(xiang)呈條狀(zhuang)且平直(zhi)的(de)(de)形(xing)態(tai)特征。圖(tu)3b為(wei)(wei)3GPa高(gao)壓(ya)(ya)(ya)(ya)(ya)熱(re)(re)(re)(re)處(chu)理(li)(li)(li)后(hou)(hou)的(de)(de)微(wei)觀組(zu)(zu)織(zhi)(zhi)，可(ke)(ke)以觀察(cha)到，條狀(zhuang)的(de)(de)α相(xiang)(xiang)有(you)熔斷現(xian)象，并(bing)且組(zu)(zu)織(zhi)(zhi)中形(xing)成大量(liang)(liang)散亂(luan)的(de)(de)細小(xiao)條狀(zhuang)α相(xiang)(xiang)。進(jin)一步對組(zu)(zu)織(zhi)(zhi)內部的(de)(de)位錯(cuo)特征進(jin)行(xing)對比分(fen)析，結(jie)果(guo)如圖(tu)4所(suo)(suo)示。可(ke)(ke)以發現(xian)，經(jing)3GPa高(gao)壓(ya)(ya)(ya)(ya)(ya)熱(re)(re)(re)(re)處(chu)理(li)(li)(li)后(hou)(hou)，組(zu)(zu)織(zhi)(zhi)中的(de)(de)位錯(cuo)密(mi)度較常(chang)壓(ya)(ya)(ya)(ya)(ya)熱(re)(re)(re)(re)處(chu)理(li)(li)(li)后(hou)(hou)的(de)(de)位錯(cuo)密(mi)度明顯(xian)提高(gao)。常(chang)壓(ya)(ya)(ya)(ya)(ya)和(he)3GPa高(gao)壓(ya)(ya)(ya)(ya)(ya)熱(re)(re)(re)(re)處(chu)理(li)(li)(li)試(shi)樣的(de)(de)XRD結(jie)果(guo)如圖(tu)5所(suo)(suo)示，可(ke)(ke)以看出，3GPa高(gao)壓(ya)(ya)(ya)(ya)(ya)熱(re)(re)(re)(re)處(chu)理(li)(li)(li)和(he)常(chang)壓(ya)(ya)(ya)(ya)(ya)熱(re)(re)(re)(re)處(chu)理(li)(li)(li)后(hou)(hou)的(de)(de)TC11鈦(tai)合(he)金組(zu)(zu)織(zhi)(zhi)均由α相(xiang)(xiang)和(he)β相(xiang)(xiang)兩相(xiang)(xiang)組(zu)(zu)成，僅是α相(xiang)(xiang)、β相(xiang)(xiang)的(de)(de)衍射峰(feng)強度和(he)峰(feng)位有(you)所(suo)(suo)不同。由此可(ke)(ke)見(jian)，高(gao)壓(ya)(ya)(ya)(ya)(ya)熱(re)(re)(re)(re)處(chu)理(li)(li)(li)能改變TC11鈦(tai)合(he)金組(zu)(zu)成相(xiang)(xiang)的(de)(de)形(xing)狀(zhuang)、大小(xiao)、數量(liang)(liang)與(yu)(yu)分(fen)布，但并(bing)未導致新相(xiang)(xiang)生(sheng)成。

對常(chang)(chang)壓和(he)高(gao)(gao)壓熱處(chu)理(li)(li)后TC11鈦(tai)合(he)金(jin)(jin)(jin)的(de)組(zu)織變化(hua)規律進行分(fen)(fen)析，認為當TC11鈦(tai)合(he)金(jin)(jin)(jin)被加(jia)熱至(zhi)1000℃時，合(he)金(jin)(jin)(jin)處(chu)在(zai)β單(dan)相(xiang)(xiang)區，在(zai)隨后的(de)冷卻過程(cheng)(cheng)中(zhong)，TC11鈦(tai)合(he)金(jin)(jin)(jin)將發生(sheng)β相(xiang)(xiang)向(xiang)α相(xiang)(xiang)轉變[19]，因此，經過常(chang)(chang)壓熱處(chu)理(li)(li)和(he)高(gao)(gao)壓熱處(chu)理(li)(li)后，TC11微觀(guan)組(zu)織由α相(xiang)(xiang)和(he)晶間β相(xiang)(xiang)組(zu)成。進一(yi)步對高(gao)(gao)壓熱處(chu)理(li)(li)后的(de)組(zu)織細(xi)化(hua)原因進行分(fen)(fen)析。研(yan)究表明，一(yi)方(fang)面(mian)(mian)在(zai)高(gao)(gao)壓熱處(chu)理(li)(li)過程(cheng)(cheng)中(zhong)，超高(gao)(gao)壓力會(hui)使合(he)金(jin)(jin)(jin)產生(sheng)內(nei)應力、基體(ti)組(zu)織中(zhong)產生(sheng)大(da)量位(wei)錯(cuo)[20]，這(zhe)為固體(ti)相(xiang)(xiang)變過程(cheng)(cheng)中(zhong)新相(xiang)(xiang)的(de)形核(he)提供了更多的(de)位(wei)置(zhi)，提高(gao)(gao)了晶核(he)的(de)成核(he)率[21]。另一(yi)方(fang)面(mian)(mian)，超高(gao)(gao)壓力會(hui)降低(di)原子(zi)的(de)擴散系數，抑制晶核(he)長大(da)[22]。故在(zai)經過高(gao)(gao)壓熱處(chu)理(li)(li)后的(de)TC11鈦(tai)合(he)金(jin)(jin)(jin)內(nei)，出現(xian)了細(xi)條狀α相(xiang)(xiang)，組(zu)織有(you)所細(xi)化(hua)。

2.2高(gao)壓熱(re)處理后TC11鈦(tai)合金力學性能

2.2.1抗(kang)塑性變形能(neng)力

TC11鈦(tai)合(he)金在(zai)常壓(ya)(ya)(ya)(ya)(ya)(ya)(ya)和(he)高壓(ya)(ya)(ya)(ya)(ya)(ya)(ya)熱(re)處理(li)(li)后(hou)納(na)(na)(na)米壓(ya)(ya)(ya)(ya)(ya)(ya)(ya)痕(hen)(hen)(hen)載荷與納(na)(na)(na)米壓(ya)(ya)(ya)(ya)(ya)(ya)(ya)痕(hen)(hen)(hen)深(shen)度(du)(du)之間的(de)關(guan)(guan)系如圖6所示。可以(yi)(yi)看出，常壓(ya)(ya)(ya)(ya)(ya)(ya)(ya)熱(re)處理(li)(li)和(he)3GPa高壓(ya)(ya)(ya)(ya)(ya)(ya)(ya)熱(re)處理(li)(li)后(hou)的(de)TC11鈦(tai)合(he)金在(zai)納(na)(na)(na)米壓(ya)(ya)(ya)(ya)(ya)(ya)(ya)痕(hen)(hen)(hen)結(jie)(jie)果曲線上均出現了(le)一個平臺(tai)，表(biao)明(ming)合(he)金發生了(le)蠕變(bian)現象。常壓(ya)(ya)(ya)(ya)(ya)(ya)(ya)熱(re)處理(li)(li)和(he)3GPa高壓(ya)(ya)(ya)(ya)(ya)(ya)(ya)熱(re)處理(li)(li)后(hou)TC11鈦(tai)合(he)金納(na)(na)(na)米壓(ya)(ya)(ya)(ya)(ya)(ya)(ya)痕(hen)(hen)(hen)結(jie)(jie)果如表(biao)2所示。在(zai)相(xiang)同載荷下，3GPa高壓(ya)(ya)(ya)(ya)(ya)(ya)(ya)熱(re)處理(li)(li)后(hou)TC11鈦(tai)合(he)金的(de)硬(ying)度(du)(du)、彈(dan)性模量(liang)分別為5.19HV和(he)128.04GPa，均高于常壓(ya)(ya)(ya)(ya)(ya)(ya)(ya)熱(re)處理(li)(li)后(hou)TC11鈦(tai)合(he)金試(shi)樣的(de)4.06HV和(he)115.68GPa。而(er)經3GPa高壓(ya)(ya)(ya)(ya)(ya)(ya)(ya)熱(re)處理(li)(li)后(hou)，TC11鈦(tai)合(he)金的(de)蠕變(bian)量(liang)、最大(da)壓(ya)(ya)(ya)(ya)(ya)(ya)(ya)痕(hen)(hen)(hen)深(shen)度(du)(du)和(he)卸(xie)載后(hou)殘留壓(ya)(ya)(ya)(ya)(ya)(ya)(ya)痕(hen)(hen)(hen)深(shen)度(du)(du)均小于常壓(ya)(ya)(ya)(ya)(ya)(ya)(ya)熱(re)處理(li)(li)后(hou)TC11鈦(tai)合(he)金試(shi)樣的(de)。相(xiang)關(guan)(guan)研究表(biao)明(ming)，納(na)(na)(na)米壓(ya)(ya)(ya)(ya)(ya)(ya)(ya)痕(hen)(hen)(hen)實驗卸(xie)載后(hou)的(de)殘余壓(ya)(ya)(ya)(ya)(ya)(ya)(ya)痕(hen)(hen)(hen)深(shen)度(du)(du)可以(yi)(yi)表(biao)征合(he)金的(de)抗(kang)塑性變(bian)形(xing)能力(li)，殘余壓(ya)(ya)(ya)(ya)(ya)(ya)(ya)痕(hen)(hen)(hen)深(shen)度(du)(du)越(yue)大(da)，表(biao)示塑性變(bian)形(xing)越(yue)大(da)[23-24]。因此，3GPa高壓(ya)(ya)(ya)(ya)(ya)(ya)(ya)熱(re)處理(li)(li)可以(yi)(yi)提(ti)高TC11鈦(tai)合(he)金的(de)塑性與變(bian)形(xing)抗(kang)力(li)。

2.2.2硬度

常壓(ya)(ya)(ya)和高(gao)(gao)(gao)壓(ya)(ya)(ya)熱(re)處理(li)(li)后(hou)TC11鈦合(he)金(jin)(jin)硬(ying)度(du)與(yu)壓(ya)(ya)(ya)力的(de)關(guan)系(xi)曲線(xian)如圖7所(suo)(suo)示，其中0GPa代表常壓(ya)(ya)(ya)熱(re)處理(li)(li)。可以(yi)明(ming)顯看(kan)出，經高(gao)(gao)(gao)壓(ya)(ya)(ya)熱(re)處理(li)(li)后(hou)，合(he)金(jin)(jin)的(de)硬(ying)度(du)高(gao)(gao)(gao)于常壓(ya)(ya)(ya)退火處理(li)(li)TC11鈦合(he)金(jin)(jin)的(de)硬(ying)度(du)（335HV）。當壓(ya)(ya)(ya)力為1~5GPa時(shi)，隨著(zhu)壓(ya)(ya)(ya)力的(de)增(zeng)大，TC11鈦合(he)金(jin)(jin)的(de)硬(ying)度(du)有所(suo)(suo)增(zeng)大，但(dan)超過3GPa以(yi)后(hou)，合(he)金(jin)(jin)的(de)硬(ying)度(du)基本沒有明(ming)顯變化。由測試結果(guo)可知，經3GPa高(gao)(gao)(gao)壓(ya)(ya)(ya)熱(re)處理(li)(li)后(hou)，TC11鈦合(he)金(jin)(jin)的(de)硬(ying)度(du)為378HV，較相同加熱(re)溫度(du)和保溫時(shi)間的(de)常壓(ya)(ya)(ya)熱(re)處理(li)(li)的(de)硬(ying)度(du)（335HV）提高(gao)(gao)(gao)了12.84%。

2.2.3抗壓強度

TC11鈦(tai)合金(jin)(jin)(jin)抗壓(ya)(ya)(ya)(ya)強(qiang)度(du)與壓(ya)(ya)(ya)(ya)力的(de)(de)關系如圖8所示。可(ke)以看(kan)到(dao)，高(gao)(gao)壓(ya)(ya)(ya)(ya)熱處理(li)后(hou)合金(jin)(jin)(jin)的(de)(de)室(shi)溫(wen)(wen)和(he)高(gao)(gao)溫(wen)(wen)抗壓(ya)(ya)(ya)(ya)強(qiang)度(du)均高(gao)(gao)于(yu)常壓(ya)(ya)(ya)(ya)熱處理(li)后(hou)合金(jin)(jin)(jin)的(de)(de)室(shi)溫(wen)(wen)和(he)高(gao)(gao)溫(wen)(wen)抗壓(ya)(ya)(ya)(ya)強(qiang)度(du)。當壓(ya)(ya)(ya)(ya)力為(wei)(wei)1~5GPa時，隨(sui)著壓(ya)(ya)(ya)(ya)力的(de)(de)增大，TC11鈦(tai)合金(jin)(jin)(jin)的(de)(de)室(shi)溫(wen)(wen)和(he)高(gao)(gao)溫(wen)(wen)抗壓(ya)(ya)(ya)(ya)強(qiang)度(du)變化不(bu)明(ming)顯。由實驗結果(guo)可(ke)知，經3GPa熱處理(li)后(hou)，TC11鈦(tai)合金(jin)(jin)(jin)的(de)(de)室(shi)溫(wen)(wen)抗壓(ya)(ya)(ya)(ya)強(qiang)度(du)和(he)400℃抗壓(ya)(ya)(ya)(ya)強(qiang)度(du)分別為(wei)(wei)1610MPa和(he)1442MPa，分別較相同(tong)加熱溫(wen)(wen)度(du)和(he)保溫(wen)(wen)時間的(de)(de)常壓(ya)(ya)(ya)(ya)退(tui)火處理(li)的(de)(de)室(shi)溫(wen)(wen)抗壓(ya)(ya)(ya)(ya)強(qiang)度(du)（1465MPa）和(he)400℃抗壓(ya)(ya)(ya)(ya)強(qiang)度(du)（1328MPa）提高(gao)(gao)了9.89%和(he)8.58%。

常壓(ya)(ya)和(he)高(gao)壓(ya)(ya)熱處理后(hou)TC11鈦(tai)合金(jin)(jin)室(shi)溫(wen)壓(ya)(ya)縮(suo)斷口(kou)形(xing)貌如(ru)圖(tu)9所示。可以看出，與(yu)常壓(ya)(ya)熱處理后(hou)的(de)相比，3GPa高(gao)壓(ya)(ya)熱處理后(hou)的(de)TC11鈦(tai)合金(jin)(jin)斷口(kou)平整(zheng)，斷口(kou)中的(de)韌窩數量(liang)明顯減少(shao)，韌窩深度(du)也顯著降(jiang)低。這也佐證了3GPa高(gao)壓(ya)(ya)熱處理后(hou)TC11鈦(tai)合金(jin)(jin)的(de)強度(du)較(jiao)常壓(ya)(ya)熱處理后(hou)的(de)強度(du)高(gao)。

2.3組(zu)織與性能(neng)相關性

對高(gao)(gao)壓(ya)熱處(chu)(chu)理(li)可以改善TC11鈦合(he)金(jin)(jin)(jin)力(li)學性(xing)能(neng)(neng)的(de)(de)原(yuan)因進行分(fen)析。研(yan)究(jiu)表明，一方面，經(jing)高(gao)(gao)壓(ya)熱處(chu)(chu)理(li)后，合(he)金(jin)(jin)(jin)組(zu)織內部(bu)存在(zai)比常壓(ya)熱處(chu)(chu)理(li)更高(gao)(gao)的(de)(de)位錯(cuo)密(mi)度(du)(du)[25]，在(zai)位錯(cuo)運動過程(cheng)中更容易發(fa)生位錯(cuo)之(zhi)間的(de)(de)交割和相互纏結，從而造(zao)成位錯(cuo)塞(sai)積，產生加工硬(ying)化效(xiao)果，提高(gao)(gao)合(he)金(jin)(jin)(jin)的(de)(de)強度(du)(du)和硬(ying)度(du)(du)力(li)學性(xing)能(neng)(neng)。另一方面，高(gao)(gao)壓(ya)熱處(chu)(chu)理(li)可以抑制元素(su)擴(kuo)散(san)速率(lv)[26]，細化TC11鈦合(he)金(jin)(jin)(jin)微觀組(zu)織，組(zu)織細化將會使(shi)塑性(xing)變形更均勻，有效(xiao)減少內應力(li)集中，更有利于提高(gao)(gao)合(he)金(jin)(jin)(jin)塑性(xing)。綜上所述，經(jing)過高(gao)(gao)壓(ya)熱處(chu)(chu)理(li)后，TC11鈦合(he)金(jin)(jin)(jin)的(de)(de)抗塑性(xing)變形能(neng)(neng)力(li)、硬(ying)度(du)(du)和抗壓(ya)強度(du)(du)等力(li)學性(xing)能(neng)(neng)得到了一定(ding)的(de)(de)提升。

3、結論

研(yan)究了高壓熱處理(li)對(dui)TC11鈦合金微(wei)觀組織和力學性能的影響，得到以下結論：

1）經過高(gao)壓熱處(chu)理后，TC11鈦合金的(de)抗(kang)塑性變形能(neng)力(li)、硬度和(he)抗(kang)壓強(qiang)度均在(zai)一(yi)定程(cheng)度上有所提高(gao)。當TC11鈦合金經3GPa壓力(li)、1000℃保溫20min熱處(chu)理后，硬度、室溫抗(kang)壓強(qiang)度和(he)400℃抗(kang)壓強(qiang)度分別為378HV、1610MPa和(he)1442MPa，較相同工藝常壓熱處(chu)理后的(de)分別提高(gao)了12.84%、9.89%和(he)8.58%。

2）對高壓(ya)熱(re)處理改(gai)善TC11鈦(tai)合(he)金(jin)(jin)力學(xue)性(xing)能的(de)機制進(jin)行分析，結果(guo)表明，高壓(ya)熱(re)處理可以細化TC11鈦(tai)合(he)金(jin)(jin)組(zu)織，增大基體的(de)位錯(cuo)密度，從而提高了TC11鈦(tai)合(he)金(jin)(jin)的(de)綜(zong)合(he)力學(xue)性(xing)能。

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