TC2合(he)金(jin)是Ti-Al-Mn系鈦(tai)合(he)金(jin)的(de)(de)(de)(de)一(yi)種(zhong),屬于α+β型(xing)(xing)鈦(tai)合(he)金(jin),在室溫平衡狀態下(xia)由α相(xiang)(xiang)和(he)少量(liang)β相(xiang)(xiang)組成(cheng)(cheng)。合(he)金(jin)具(ju)有較(jiao)(jiao)高(gao)的(de)(de)(de)(de)強度、良(liang)好的(de)(de)(de)(de)塑性(xing)(xing)和(he)可(ke)焊接(jie)性(xing)(xing),通常用(yong)板(ban)材(cai)沖(chong)壓加(jia)工(gong)成(cheng)(cheng)薄(bo)壁型(xing)(xing)零件,并經過焊接(jie)制成(cheng)(cheng)飛(fei)機、發動機部(bu)件。目(mu)前在我國新一(yi)代(dai)的(de)(de)(de)(de)高(gao)性(xing)(xing)能(neng)新型(xing)(xing)戰斗(dou)機上已獲得(de)大(da)量(liang)應用(yong)。其中(zhong),寬(kuan)幅(fu)薄(bo)板(ban)(寬(kuan)1~1.5m)是瓶頸材(cai)料(liao)之一(yi),我國生(sheng)(sheng)產(chan)的(de)(de)(de)(de)TC2鈦(tai)合(he)金(jin)薄(bo)板(ban)在尺寸精度、板(ban)形(xing)(xing)(xing)、表面(mian)(mian)質(zhi)量(liang)方(fang)面(mian)(mian)與國外還存(cun)在一(yi)定(ding)(ding)差距。目(mu)前國內生(sheng)(sheng)產(chan)的(de)(de)(de)(de)TC2鈦(tai)合(he)金(jin)薄(bo)板(ban)幅(fu)面(mian)(mian)較(jiao)(jiao)窄,在加(jia)工(gong)大(da)型(xing)(xing)零件時焊縫過多,對其使用(yong)性(xing)(xing)能(neng)產(chan)生(sheng)(sheng)很大(da)影響。鈦(tai)板(ban)因軋制工(gong)藝問題(ti),微觀組織不均勻(yun),導致(zhi)其存(cun)在各向(xiang)異性(xing)(xing),成(cheng)(cheng)形(xing)(xing)(xing)性(xing)(xing)不穩定(ding)(ding),高(gao)性(xing)(xing)能(neng)薄(bo)板(ban)的(de)(de)(de)(de)板(ban)形(xing)(xing)(xing)控制技術較(jiao)(jiao)弱。因此,國內航(hang)空航(hang)天應用(yong)所需(xu)大(da)規格(ge)高(gao)性(xing)(xing)能(neng)TC2鈦(tai)合(he)金(jin)薄(bo)板(ban)尚需(xu)大(da)量(liang)進(jin)口。隨著我國大(da)型(xing)(xing)運輸機、大(da)飛(fei)機項目(mu)的(de)(de)(de)(de)開展,航(hang)空用(yong)鈦(tai)需(xu)求將會(hui)大(da)幅(fu)增加(jia)。科研人員(yuan)針對上述問題(ti),開展相(xiang)(xiang)應的(de)(de)(de)(de)先進(jin)大(da)規格(ge)高(gao)性(xing)(xing)能(neng)TC2鈦(tai)合(he)金(jin)薄(bo)板(ban)材(cai)制備技術研究,以滿足國內軍工(gong)、大(da)型(xing)(xing)裝備制造等方(fang)面(mian)(mian)的(de)(de)(de)(de)相(xiang)(xiang)應需(xu)求。
試驗采用(yong)3t真(zhen)空自耗電弧(hu)爐(lu)熔煉大(da)規(gui)格TC2鈦(tai)合(he)金鑄錠。板(ban)坯(pi)鍛造和板(ban)材熱軋(ya)(ya)分(fen)別在25MN快鍛機和2800mm四(si)輥可逆熱軋(ya)(ya)機組上進行(xing)(xing)(xing)。疊(die)(die)軋(ya)(ya)坯(pi)料為(wei)(wei)3~5mm厚熱軋(ya)(ya)鈦(tai)合(he)金板(ban),疊(die)(die)軋(ya)(ya)用(yong)坯(pi)料表面(mian)進行(xing)(xing)(xing)特殊處(chu)(chu)理,防止焊(han)(han)合(he)及粘連。每2~4片為(wei)(wei)一組疊(die)(die)在一起。上下(xia)采用(yong)合(he)適厚度(du)的鋼板(ban)包覆并進行(xing)(xing)(xing)封焊(han)(han),制(zhi)成(cheng)疊(die)(die)軋(ya)(ya)包。疊(die)(die)軋(ya)(ya)工(gong)藝(yi)A為(wei)(wei)自主開發(fa)的鈦(tai)合(he)金包套疊(die)(die)軋(ya)(ya)工(gong)藝(yi),包套疊(die)(die)軋(ya)(ya)在2800四(si)輥可逆熱軋(ya)(ya)機組上進行(xing)(xing)(xing),軋(ya)(ya)制(zhi)溫度(du)為(wei)(wei)Tβ-50℃,采用(yong)交(jiao)叉軋(ya)(ya)制(zhi),總變形量達(da)到80%。疊(die)(die)軋(ya)(ya)工(gong)藝(yi)B為(wei)(wei)單(dan)向軋(ya)(ya)制(zhi),軋(ya)(ya)制(zhi)溫度(du)為(wei)(wei)Tβ-50℃,總變形量達(da)到80%。疊(die)(die)軋(ya)(ya)后直(zhi)接(jie)進行(xing)(xing)(xing)退火熱處(chu)(chu)理。退火后切邊拆包,獲(huo)得規(gui)格為(wei)(wei)0.6mm×1200mm×Lmm的TC2鈦(tai)合(he)金薄板(ban)。在MTS試驗機上進行(xing)(xing)(xing)室溫拉伸試驗,采用(yong)奧林巴斯顯(xian)微鏡(jing)觀察(cha)金相組織。試驗結(jie)果表明:
(1)采用包覆疊軋(ya)在兩相區(qu)軋(ya)制(zhi)大規(gui)格TC2合(he)金薄板,得(de)到的板材具(ju)有細小、均勻的等軸(zhou)組織。
(2)采用交叉軋制工藝A進行(xing)包覆疊軋可獲得均勻(yun)的組織及(ji)較好的室(shi)溫強度和塑性匹配,橫縱向性能均勻(yun)一致,利(li)于(yu)后續板(ban)材(cai)加工成形。
(3)采用單向軋(ya)制工藝B進行包(bao)覆疊軋(ya)也(ye)可獲(huo)得較好的室(shi)溫強度(du)和塑性(xing)匹配, 但金相組織(zhi)存(cun)在(zai)部(bu)分條狀組織(zhi),橫縱向性(xing)能(neng)存(cun)在(zai)較大差異。
