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鈦(tai)合金鍛造變形程度對鈦(tai)合金鍛件(jian)的(de)組織和力學性能(neng)有哪(na)些(xie)影響?

發布時間：2021-07-09 11:49:09 丨 瀏覽次數：

　　變形(xing)(xing)程(cheng)度(du)(du)(du)與變形(xing)(xing)溫(wen)(wen)度(du)(du)(du)對(dui)鈦(tai)合(he)金(jin)鍛件組(zu)(zu)織和力學性(xing)能(neng)的影響(xiang)(xiang)是相互作用(yong)的鈦(tai)合(he)金(jin)變形(xing)(xing)程(cheng)度(du)(du)(du)對(dui)高(gao)低倍組(zu)(zu)織有重(zhong)要(yao)的影響(xiang)(xiang),變形(xing)(xing)程(cheng)度(du)(du)(du)大(da)(da)(da)于(yu)30%~40%時(shi),鈦(tai)合(he)金(jin)組(zu)(zu)織明顯出(chu)現細(xi)化(hua)。為(wei)使(shi)粗晶針狀組(zu)(zu)織充(chong)分細(xi)化(hua)并(bing)轉(zhuan)變為(wei)球狀組(zu)(zu)織,變形(xing)(xing)溫(wen)(wen)度(du)(du)(du)必須(xu)控制在兩相區內,而且變形(xing)(xing)程(cheng)度(du)(du)(du)應(ying)不(bu)小于(yu)60%~70%。變形(xing)(xing)程(cheng)度(du)(du)(du)大(da)(da)(da)小應(ying)保證形(xing)(xing)成介于(yu)針狀和等軸(zhou)狀組(zu)(zu)織之間(jian)的中間(jian)組(zu)(zu)織。在高(gao)于(yu)B轉(zhuan)變溫(wen)(wen)度(du)(du)(du)下進行(xing)塑性(xing)變形(xing)(xing)程(cheng)度(du)(du)(du)也要(yao)足(zu)夠大(da)(da)(da),才(cai)能(neng)有效地(di)細(xi)化(hua)B晶粒。并(bing)且,變形(xing)(xing)溫(wen)(wen)度(du)(du)(du)越高(gao),所需的變形(xing)(xing)程(cheng)度(du)(du)(du)也越大(da)(da)(da)。

　　如果(guo)合金(jin)在(zai)(zai)B相(xiang)(xiang)(xiang)區(qu)變(bian)(bian)形(xing)之前先在(zai)(zai)(a+B)相(xiang)(xiang)(xiang)區(qu)進(jin)行塑性變(bian)(bian)形(xing),在(zai)(zai)B相(xiang)(xiang)(xiang)區(qu)變(bian)(bian)形(xing)時,只(zhi)要在(zai)(zai)不太(tai)大的(de)變(bian)(bian)形(xing)程度(30%~40%)下便可(ke)以使組(zu)織得到細化。其原因在(zai)(zai)于,經過(a+B)相(xiang)(xiang)(xiang)區(qu)鍛造的(de)合金(jin)儲(chu)備了充分的(de)變(bian)(bian)形(xing)能(neng)和更多的(de)位錯,再在(zai)(zai)B相(xiang)(xiang)(xiang)區(qu)變(bian)(bian)形(xing)時,發生(sheng)一次再結品,使得在(zai)(zai)阝(fu)相(xiang)(xiang)(xiang)區(qu)變(bian)(bian)形(xing)對合金(jin)的(de)晶粒細化更為有效。

　　但(dan)是,在(zai)(zai)B轉(zhuan)變(bian)溫(wen)(wen)(wen)度(du)(du)(du)(du)以上鍛(duan)成的(de)(de)(de)(de)(de)(de)(de)模鍛(duan)件中,往往達不到(dao)上述細化(hua)晶(jing)(jing)粒(li)(li)的(de)(de)(de)(de)(de)(de)(de)效果。原(yuan)因在(zai)(zai)于模鍛(duan)件尺寸大,金屬在(zai)(zai)B相區(qu)的(de)(de)(de)(de)(de)(de)(de)溫(wen)(wen)(wen)度(du)(du)(du)(du)下(xia)停(ting)留(liu)的(de)(de)(de)(de)(de)(de)(de)時間長。特別是在(zai)(zai)模鍛(duan)件的(de)(de)(de)(de)(de)(de)(de)難(nan)變(bian)形(xing)(xing)(xing)(xing)(xing)區(qu)內(nei)(nei),一般都(dou)出(chu)現粗晶(jing)(jing)組(zu)(zu)織(zhi),因為(wei)(wei)這(zhe)些部位變(bian)形(xing)(xing)(xing)(xing)(xing)程(cheng)度(du)(du)(du)(du)小(xiao),沒有產(chan)生一次再(zai)結晶(jing)(jing)(B晶(jing)(jing)粒(li)(li)再(zai)結晶(jing)(jing)),而(er)原(yuan)晶(jing)(jing)粒(li)(li)卻發生劇烈長大。變(bian)形(xing)(xing)(xing)(xing)(xing)程(cheng)度(du)(du)(du)(du)的(de)(de)(de)(de)(de)(de)(de)改(gai)變(bian)不僅影(ying)(ying)(ying)響(xiang)到(dao)晶(jing)(jing)粒(li)(li)度(du)(du)(du)(du),而(er)且也(ye)對晶(jing)(jing)內(nei)(nei)針狀(zhuang)(片狀(zhuang))組(zu)(zu)織(zhi)有影(ying)(ying)(ying)響(xiang),變(bian)形(xing)(xing)(xing)(xing)(xing)程(cheng)度(du)(du)(du)(du)增(zeng)大會(hui)使晶(jing)(jing)內(nei)(nei)組(zu)(zu)織(zhi)得(de)到(dao)細化(hua)。與(yu)變(bian)形(xing)(xing)(xing)(xing)(xing)溫(wen)(wen)(wen)度(du)(du)(du)(du)的(de)(de)(de)(de)(de)(de)(de)影(ying)(ying)(ying)響(xiang)一樣,變(bian)形(xing)(xing)(xing)(xing)(xing)程(cheng)度(du)(du)(du)(du)影(ying)(ying)(ying)響(xiang)最明(ming)顯(xian)的(de)(de)(de)(de)(de)(de)(de)是在(zai)(zai)(a+B)相區(qu)的(de)(de)(de)(de)(de)(de)(de)溫(wen)(wen)(wen)度(du)(du)(du)(du)下(xia),因為(wei)(wei)這(zhe)時有a相存在(zai)(zai),而(er)a相經受了(le)塑(su)性變(bian)形(xing)(xing)(xing)(xing)(xing)在(zai)(zai)(a+B)相區(qu)的(de)(de)(de)(de)(de)(de)(de)溫(wen)(wen)(wen)度(du)(du)(du)(du)下(xia),變(bian)形(xing)(xing)(xing)(xing)(xing)程(cheng)度(du)(du)(du)(du)的(de)(de)(de)(de)(de)(de)(de)變(bian)化(hua),對力學(xue)性能(neng),尤其(qi)塑(su)性的(de)(de)(de)(de)(de)(de)(de)影(ying)(ying)(ying)響(xiang)要比在(zai)(zai)單相區(qu)的(de)(de)(de)(de)(de)(de)(de)更為(wei)(wei)顯(xian)著(zhu)。在(zai)(zai)B相區(qu)塑(su)性變(bian)形(xing)(xing)(xing)(xing)(xing)時,變(bian)形(xing)(xing)(xing)(xing)(xing)溫(wen)(wen)(wen)度(du)(du)(du)(du)的(de)(de)(de)(de)(de)(de)(de)提高會(hui)使變(bian)形(xing)(xing)(xing)(xing)(xing)程(cheng)度(du)(du)(du)(du)對力學(xue)性能(neng)的(de)(de)(de)(de)(de)(de)(de)影(ying)(ying)(ying)響(xiang)減(jian)小(xiao)。例如,TC6合金鑄錠在(zai)(zai)高于B轉(zhuan)變(bian)溫(wen)(wen)(wen)度(du)(du)(du)(du)(1050℃)鍛(duan)造時,隨著(zhu)變(bian)形(xing)(xing)(xing)(xing)(xing)程(cheng)度(du)(du)(du)(du)的(de)(de)(de)(de)(de)(de)(de)增(zeng)大,低倍組(zu)(zu)織(zhi)逐(zhu)漸變(bian)的(de)(de)(de)(de)(de)(de)(de)細化(hua):變(bian)形(xing)(xing)(xing)(xing)(xing)程(cheng)度(du)(du)(du)(du)為(wei)(wei)15%時,鑄態(tai)組(zu)(zu)織(zhi)未破碎(sui);變(bian)形(xing)(xing)(xing)(xing)(xing)程(cheng)度(du)(du)(du)(du)為(wei)(wei)30%時,鑄態(tai)組(zu)(zu)織(zhi)輕(qing)微破碎(sui),略呈纖維狀(zhuang);變(bian)形(xing)(xing)(xing)(xing)(xing)程(cheng)度(du)(du)(du)(du)為(wei)(wei)60%時,呈明(ming)顯(xian)的(de)(de)(de)(de)(de)(de)(de)纖維狀(zhuang),但(dan)還(huan)留(liu)有較清晰(xi)的(de)(de)(de)(de)(de)(de)(de)鑄態(tai)組(zu)(zu)織(zhi);當變(bian)形(xing)(xing)(xing)(xing)(xing)程(cheng)度(du)(du)(du)(du)增(zeng)大至80%時,呈細小(xiao)纖維狀(zhuang)組(zu)(zu)織(zhi),但(dan)仍留(liu)有鑄態(tai)組(zu)(zu)織(zhi)的(de)(de)(de)(de)(de)(de)(de)痕跡。