一(yi)、氮氣孔(kong)的形(xing)成機理

  在(zai)(zai)21.5Cr5Mn1.5Ni0.25N含氮(dan)(dan)(dan)(dan)(dan)(dan)雙相(xiang)(xiang)(xiang)(xiang)(xiang)鋼凝(ning)固(gu)(gu)過(guo)程中(zhong)(zhong)(zhong)，氮(dan)(dan)(dan)(dan)(dan)(dan)氣(qi)孔形成(cheng)(cheng)和(he)凝(ning)固(gu)(gu)前沿(yan)處［％N]1iq隨(sui)距離變化的(de)(de)(de)規律如圖(tu)(tu)2-55所示(shi)。由(you)于糊(hu)狀(zhuang)(zhuang)(zhuang)區內(nei)大(da)量枝晶(jing)網狀(zhuang)(zhuang)(zhuang)結構的(de)(de)(de)形成(cheng)(cheng)，液(ye)相(xiang)(xiang)(xiang)(xiang)(xiang)的(de)(de)(de)對流只存在(zai)(zai)于一(yi)次枝晶(jing)尖端位置附(fu)近。且枝晶(jing)間幾乎(hu)無液(ye)相(xiang)(xiang)(xiang)(xiang)(xiang)的(de)(de)(de)流動。因此，枝晶(jing)間殘(can)(can)余(yu)(yu)液(ye)相(xiang)(xiang)(xiang)(xiang)(xiang)中(zhong)(zhong)(zhong)的(de)(de)(de)氮(dan)(dan)(dan)(dan)(dan)(dan)傳質(zhi)主(zhu)要依靠(kao)氮(dan)(dan)(dan)(dan)(dan)(dan)的(de)(de)(de)擴散(san)行(xing)為，且糊(hu)狀(zhuang)(zhuang)(zhuang)區內(nei)氮(dan)(dan)(dan)(dan)(dan)(dan)傳質(zhi)速(su)(su)率(lv)非(fei)常小。初始(shi)相(xiang)(xiang)(xiang)(xiang)(xiang)貧氮(dan)(dan)(dan)(dan)(dan)(dan)鐵(tie)素體相(xiang)(xiang)(xiang)(xiang)(xiang)8的(de)(de)(de)氮(dan)(dan)(dan)(dan)(dan)(dan)溶(rong)解(jie)度(du)和(he)糊(hu)狀(zhuang)(zhuang)(zhuang)區的(de)(de)(de)氮(dan)(dan)(dan)(dan)(dan)(dan)傳質(zhi)速(su)(su)率(lv)較低，導致在(zai)(zai)貧氮(dan)(dan)(dan)(dan)(dan)(dan)鐵(tie)素體相(xiang)(xiang)(xiang)(xiang)(xiang)枝晶(jing)附(fu)近的(de)(de)(de)液(ye)相(xiang)(xiang)(xiang)(xiang)(xiang)中(zhong)(zhong)(zhong)出現(xian)氮(dan)(dan)(dan)(dan)(dan)(dan)富(fu)集，且［％N]iq迅速(su)(su)增(zeng)大(da)，如圖(tu)(tu)2-55(a)所示(shi)。根據Yang和(he) Leel70]、Svyazhin 等、Ridolfi 和(he) Tassal的(de)(de)(de)報道可(ke)知，當［％N]iq的(de)(de)(de)最大(da)值超(chao)過(guo)氮(dan)(dan)(dan)(dan)(dan)(dan)氣(qi)泡形成(cheng)(cheng)的(de)(de)(de)臨界氮(dan)(dan)(dan)(dan)(dan)(dan)質(zhi)量分數(shu)（［％N]pore)時，該區域有氣(qi)泡形成(cheng)(cheng)的(de)(de)(de)可(ke)能性(xing)，如圖(tu)(tu)2-55(b)所示(shi)。在(zai)(zai)后續(xu)的(de)(de)(de)凝(ning)固(gu)(gu)過(guo)程中(zhong)(zhong)(zhong)，隨(sui)著包晶(jing)反應的(de)(de)(de)進(jin)行(xing)，富(fu)氮(dan)(dan)(dan)(dan)(dan)(dan)奧氏體相(xiang)(xiang)(xiang)(xiang)(xiang)γ以(yi)異質(zhi)形核(he)的(de)(de)(de)方式在(zai)(zai)鐵(tie)素體相(xiang)(xiang)(xiang)(xiang)(xiang)8枝晶(jing)的(de)(de)(de)表面(mian)(mian)開始(shi)形核(he)長(chang)大(da)，逐漸包裹鐵(tie)素體相(xiang)(xiang)(xiang)(xiang)(xiang)枝晶(jing)表面(mian)(mian)，并(bing)(bing)開始(shi)捕(bu)獲(huo)(huo)殘(can)(can)余(yu)(yu)液(ye)相(xiang)(xiang)(xiang)(xiang)(xiang)中(zhong)(zhong)(zhong)的(de)(de)(de)氮(dan)(dan)(dan)(dan)(dan)(dan)氣(qi)泡，對比圖(tu)(tu)2-51和(he)圖(tu)(tu)2-56可(ke)知，此時枝晶(jing)間殘(can)(can)余(yu)(yu)［％N]1ig的(de)(de)(de)增(zeng)長(chang)速(su)(su)率(lv)減小。對平(ping)衡凝(ning)固(gu)(gu)而言，殘(can)(can)余(yu)(yu)液(ye)相(xiang)(xiang)(xiang)(xiang)(xiang)中(zhong)(zhong)(zhong)氮(dan)(dan)(dan)(dan)(dan)(dan)氣(qi)泡形成(cheng)(cheng)以(yi)后，氮(dan)(dan)(dan)(dan)(dan)(dan)的(de)(de)(de)富(fu)集程度(du)減弱(ruo)，［％N]1iq增(zeng)長(chang)速(su)(su)率(lv)的(de)(de)(de)減小程度(du)明(ming)顯；相(xiang)(xiang)(xiang)(xiang)(xiang)比之下，Scheil凝(ning)固(gu)(gu)過(guo)程中(zhong)(zhong)(zhong)，氮(dan)(dan)(dan)(dan)(dan)(dan)氣(qi)泡形成(cheng)(cheng)以(yi)后，殘(can)(can)余(yu)(yu)液(ye)相(xiang)(xiang)(xiang)(xiang)(xiang)中(zhong)(zhong)(zhong)氮(dan)(dan)(dan)(dan)(dan)(dan)富(fu)集狀(zhuang)(zhuang)(zhuang)態有所緩解(jie)，但幅度(du)很小。隨(sui)著凝(ning)固(gu)(gu)界面(mian)(mian)的(de)(de)(de)進(jin)一(yi)步推移，被(bei)捕(bu)獲(huo)(huo)的(de)(de)(de)氮(dan)(dan)(dan)(dan)(dan)(dan)氣(qi)泡在(zai)(zai)奧氏體相(xiang)(xiang)(xiang)(xiang)(xiang)表面(mian)(mian)開始(shi)長(chang)大(da)，并(bing)(bing)沿(yan)凝(ning)固(gu)(gu)方向拉長(chang)，如圖(tu)(tu)2-55(c)所示(shi)。

  氮氣(qi)孔(kong)(kong)沿徑向生長(chang)(chang)，生長(chang)(chang)方向與凝(ning)固(gu)(gu)方向一致，那么氮氣(qi)孔(kong)(kong)初始(shi)(shi)形(xing)成位(wei)置(zhi)靠近鑄(zhu)錠邊部，且氮氣(qi)泡初始(shi)(shi)位(wei)置(zhi)邊緣(yuan)全由(you)奧氏(shi)體相γ構成（圖2-57中I區），與圖2-55描述(shu)相符。隨(sui)著氮氣(qi)孔(kong)(kong)被拉長(chang)(chang)，鐵素體相和奧氏(shi)體相以體積分數(shu)比約為0.92的關系交替在氮氣(qi)泡周圍形(xing)成，直到氮氣(qi)孔(kong)(kong)閉合。凝(ning)固(gu)(gu)結(jie)(jie)束后(hou)，氮氣(qi)孔(kong)(kong)的宏觀(guan)形(xing)貌類似于橢圓形(xing)，與Wei等的研究結(jie)(jie)果一致

二、氮微(wei)觀偏(pian)析對氮氣孔的影響

  氮(dan)(dan)(dan)的(de)(de)分(fen)配系(xi)數(shu)(shu)較小(xiao)，導致液(ye)(ye)(ye)相向固(gu)相轉(zhuan)(zhuan)變的(de)(de)過程中(zhong)，固(gu)相會(hui)將多(duo)(duo)(duo)余(yu)(yu)的(de)(de)氮(dan)(dan)(dan)轉(zhuan)(zhuan)移到(dao)殘余(yu)(yu)液(ye)(ye)(ye)相中(zhong)，形(xing)成(cheng)(cheng)(cheng)(cheng)氮(dan)(dan)(dan)偏(pian)析(xi)。在(zai)氮(dan)(dan)(dan)偏(pian)析(xi)程度(du)(du)逐(zhu)漸加重的(de)(de)過程中(zhong)，當殘余(yu)(yu)液(ye)(ye)(ye)相中(zhong)氮(dan)(dan)(dan)質量分(fen)數(shu)(shu)超過其(qi)飽和度(du)(du)時(shi)，極(ji)易形(xing)成(cheng)(cheng)(cheng)(cheng)氮(dan)(dan)(dan)氣(qi)泡(pao)。隨著凝(ning)(ning)固(gu)的(de)(de)進行(xing)，若氣(qi)泡(pao)無法上浮而被捕獲，凝(ning)(ning)固(gu)結束后就會(hui)在(zai)鑄(zhu)錠內部(bu)形(xing)成(cheng)(cheng)(cheng)(cheng)氣(qi)孔(kong)(kong)。因此，凝(ning)(ning)固(gu)過程中(zhong)氮(dan)(dan)(dan)偏(pian)析(xi)和溶解度(du)(du)對鑄(zhu)錠中(zhong)最終氮(dan)(dan)(dan)氣(qi)孔(kong)(kong)的(de)(de)形(xing)成(cheng)(cheng)(cheng)(cheng)有至關重要的(de)(de)作用。氮(dan)(dan)(dan)氣(qi)孔(kong)(kong)多(duo)(duo)(duo)數(shu)(shu)情(qing)況(kuang)下與疏(shu)(shu)松(song)(song)縮孔(kong)(kong)共(gong)存，內壁凹凸不(bu)平呈現裂紋狀(zhuang)，且(qie)整個(ge)氣(qi)孔(kong)(kong)形(xing)狀(zhuang)不(bu)規則，如圖2-58所示。此類氣(qi)孔(kong)(kong)不(bu)僅與鋼液(ye)(ye)(ye)中(zhong)氣(qi)泡(pao)的(de)(de)形(xing)成(cheng)(cheng)(cheng)(cheng)有關，還(huan)受凝(ning)(ning)固(gu)收縮等(deng)(deng)(deng)因素的(de)(de)影(ying)響，且(qie)多(duo)(duo)(duo)數(shu)(shu)分(fen)布于鑄(zhu)錠心部(bu)，尤其(qi)在(zai)中(zhong)心等(deng)(deng)(deng)軸晶(jing)區。這主要由于中(zhong)心等(deng)(deng)(deng)軸晶(jing)區內枝晶(jing)生(sheng)長(chang)較發達，容易形(xing)成(cheng)(cheng)(cheng)(cheng)復雜的(de)(de)網(wang)狀(zhuang)結構，從而將液(ye)(ye)(ye)相分(fen)割成(cheng)(cheng)(cheng)(cheng)無數(shu)(shu)個(ge)獨(du)立的(de)(de)液(ye)(ye)(ye)相區域，當發生(sheng)凝(ning)(ning)固(gu)收縮時(shi)，難以進行(xing)補縮，在(zai)形(xing)成(cheng)(cheng)(cheng)(cheng)疏(shu)(shu)松(song)(song)縮孔(kong)(kong)的(de)(de)同時(shi)，局(ju)部(bu)鋼液(ye)(ye)(ye)靜壓(ya)力降低，促使氮(dan)(dan)(dan)從殘余(yu)(yu)液(ye)(ye)(ye)相中(zhong)析(xi)出(chu)，從而形(xing)成(cheng)(cheng)(cheng)(cheng)了氮(dan)(dan)(dan)氣(qi)孔(kong)(kong)和疏(shu)(shu)松(song)(song)縮孔(kong)(kong)共(gong)存的(de)(de)宏(hong)觀(guan)缺陷。

  平(ping)衡凝(ning)(ning)固(gu)時，19Cr14Mn0.9N含氮(dan)(dan)(dan)(dan)(dan)奧(ao)氏體不(bu)(bu)銹鋼(gang)(gang)殘(can)余液相中(zhong)氮(dan)(dan)(dan)(dan)(dan)偏析(xi)與體系(xi)氮(dan)(dan)(dan)(dan)(dan)溶解度的(de)(de)差(cha)值(zhi)如圖2-59所示。凝(ning)(ning)固(gu)初期鐵素(su)體阱（ferrite trap)的(de)(de)形成，導致(zhi)氮(dan)(dan)(dan)(dan)(dan)溶解度的(de)(de)降低，進而使氮(dan)(dan)(dan)(dan)(dan)偏析(xi)與體系(xi)氮(dan)(dan)(dan)(dan)(dan)溶解度差(cha)值(zhi)呈現出略(lve)微增(zeng)大(da)的(de)(de)趨勢(shi)。但(dan)在后(hou)續凝(ning)(ning)固(gu)過程(cheng)中(zhong)，隨著鐵素(su)體阱的(de)(de)消(xiao)失以及富氮(dan)(dan)(dan)(dan)(dan)奧(ao)氏體相的(de)(de)不(bu)(bu)斷形成，差(cha)值(zhi)減(jian)小；在整個凝(ning)(ning)固(gu)過程(cheng)中(zhong)差(cha)值(zhi)始(shi)終較小，且變化幅度較窄(zhai)。對于19Cr14Mn0.9N 含氮(dan)(dan)(dan)(dan)(dan)奧(ao)氏體不(bu)(bu)銹鋼(gang)(gang)，液相中(zhong)氮(dan)(dan)(dan)(dan)(dan)氣泡的(de)(de)形成趨勢(shi)較小，難以在鑄錠內形成獨立內壁光滑的(de)(de)規(gui)則氮(dan)(dan)(dan)(dan)(dan)氣孔。

  此外，目前有人對(dui)奧氏(shi)體鋼凝(ning)固過程中(zhong)(zhong)氮(dan)(dan)氣(qi)(qi)(qi)孔(kong)的(de)(de)(de)形(xing)(xing)(xing)成(cheng)進行(xing)(xing)了大(da)(da)量(liang)研(yan)(yan)究，如(ru)Yang和(he)Leel901研(yan)(yan)究了奧氏(shi)體鋼16Cr3NixMn(x=9和(he)11)凝(ning)固過程中(zhong)(zhong)壓力和(he)初始氮(dan)(dan)質量(liang)分數等因素(su)對(dui)氮(dan)(dan)氣(qi)(qi)(qi)孔(kong)形(xing)(xing)(xing)成(cheng)的(de)(de)(de)影(ying)響規律(lv)，并(bing)建立(li)了相(xiang)(xiang)應的(de)(de)(de)預測模(mo)型。Ridolfi和(he)Tassal[84]分析了氮(dan)(dan)偏(pian)(pian)析、合金(jin)(jin)元(yuan)素(su)、冷(leng)卻速率以及枝晶間距對(dui)奧氏(shi)體鋼中(zhong)(zhong)氮(dan)(dan)氣(qi)(qi)(qi)孔(kong)的(de)(de)(de)影(ying)響規律(lv)，并(bing)揭示了奧氏(shi)體鋼中(zhong)(zhong)氮(dan)(dan)氣(qi)(qi)(qi)孔(kong)形(xing)(xing)(xing)成(cheng)機(ji)理(li)。然而，目前對(dui)于(yu)雙(shuang)相(xiang)(xiang)鋼中(zhong)(zhong)氮(dan)(dan)氣(qi)(qi)(qi)孔(kong)形(xing)(xing)(xing)成(cheng)的(de)(de)(de)研(yan)(yan)究較少，且主要集(ji)中(zhong)(zhong)在合金(jin)(jin)元(yuan)素(su)、鑄造方式、冷(leng)卻速率等因素(su)對(dui)氮(dan)(dan)氣(qi)(qi)(qi)孔(kong)影(ying)響規律(lv)的(de)(de)(de)研(yan)(yan)究，鮮有對(dui)雙(shuang)相(xiang)(xiang)鋼中(zhong)(zhong)氮(dan)(dan)氣(qi)(qi)(qi)孔(kong)形(xing)(xing)(xing)成(cheng)機(ji)理(li)的(de)(de)(de)報道。以21.5Cr5Mn1.5Ni0.25N含氮(dan)(dan)雙(shuang)相(xiang)(xiang)鋼為例，氮(dan)(dan)偏(pian)(pian)析與溶(rong)解度(du)(du)的(de)(de)(de)差(cha)值在整個凝(ning)固過程中(zhong)(zhong)的(de)(de)(de)變化趨(qu)(qu)勢(shi)(shi)，如(ru)圖2-59所(suo)示。隨(sui)著凝(ning)固的(de)(de)(de)進行(xing)(xing)，氮(dan)(dan)偏(pian)(pian)析始終(zhong)大(da)(da)于(yu)氮(dan)(dan)溶(rong)解度(du)(du)，且差(cha)值呈現出快速增大(da)(da)的(de)(de)(de)趨(qu)(qu)勢(shi)(shi)。因此，在21.5Cr5Mn1.5Ni0.25N 含氮(dan)(dan)雙(shuang)相(xiang)(xiang)鋼凝(ning)固過程中(zhong)(zhong)，氮(dan)(dan)偏(pian)(pian)析嚴重，殘余液相(xiang)(xiang)內氮(dan)(dan)氣(qi)(qi)(qi)泡形(xing)(xing)(xing)成(cheng)趨(qu)(qu)勢(shi)(shi)較大(da)(da)，明顯高于(yu)19Cr14Mn0.9N含氮(dan)(dan)奧氏(shi)體不銹鋼。

  氮氣(qi)泡形成和(he)長大具有重要(yao)的(de)(de)作用（圖2-60).其中(zhong)，σ為氣(qi)液(ye)界面的(de)(de)表(biao)面張力(li)，r為氣(qi)泡半徑。結合經(jing)典形核理論，氮氣(qi)泡在鋼液(ye)中(zhong)穩定存在的(de)(de)必要(yao)條(tiao)件為氣(qi)泡內壓力(li)大于作用于氣(qi)泡的(de)(de)所有壓力(li)之和(he)，即

  式中(zhong)，Aso由(you)凝(ning)固(gu)過(guo)程中(zhong)除氮(dan)(dan)以外(wai)其他合金元(yuan)素的(de)(de)微觀(guan)偏析(xi)(xi)進行計(ji)算(suan)，其值隨著枝晶間(jian)殘余(yu)液(ye)相(xiang)中(zhong)氮(dan)(dan)溶(rong)解(jie)度的(de)(de)增加而減小，表(biao)征(zheng)了枝晶間(jian)殘余(yu)液(ye)相(xiang)中(zhong)氮(dan)(dan)溶(rong)解(jie)度對氮(dan)(dan)氣(qi)泡(pao)形成(cheng)的(de)(de)影響(xiang)程度；Ase表(biao)征(zheng)了枝晶間(jian)氮(dan)(dan)偏析(xi)(xi)對氮(dan)(dan)氣(qi)泡(pao)形成(cheng)的(de)(de)影響(xiang)程度，可由(you)凝(ning)固(gu)過(guo)程中(zhong)枝晶間(jian)殘余(yu)液(ye)相(xiang)中(zhong)氮(dan)(dan)偏析(xi)(xi)計(ji)算(suan)獲得，其值隨著氮(dan)(dan)偏析(xi)(xi)的(de)(de)增大(da)而增大(da)。此外(wai)，用于計(ji)算(suan)Aso和Ase時(shi)所(suo)需的(de)(de)合金元(yuan)素偏析(xi)(xi)均由(you)鋼凝(ning)固(gu)相(xiang)變所(suo)致。

  氮(dan)氣(qi)泡的(de)(de)(de)形核和(he)(he)長(chang)大過程(cheng)(cheng)復雜，且影響因(yin)素眾多(duo)，包(bao)括(kuo)凝(ning)固(gu)(gu)收縮、冶煉環境以(yi)及坩堝材質等(deng)。因(yin)此，很難(nan)采用Pg值精確預(yu)測(ce)凝(ning)固(gu)(gu)過程(cheng)(cheng)中(zhong)氮(dan)氣(qi)泡的(de)(de)(de)形成和(he)(he)長(chang)大。然而基于Yang等(deng)的(de)(de)(de)實驗研究(jiu)［70,77],在評(ping)估凝(ning)固(gu)(gu)壓力、合金成分(fen)(fen)等(deng)因(yin)素對(dui)氮(dan)氣(qi)泡形成的(de)(de)(de)影響程(cheng)(cheng)度時，Pg起(qi)關鍵作(zuo)用。實際(ji)凝(ning)固(gu)(gu)過程(cheng)(cheng)介于平(ping)衡凝(ning)固(gu)(gu)（固(gu)(gu)／液相(xiang)中(zhong)溶(rong)質完(wan)全擴散）和(he)(he)Scheil凝(ning)固(gu)(gu)（固(gu)(gu)相(xiang)無溶(rong)質擴散，液相(xiang)中(zhong)完(wan)全擴散）之(zhi)間70].因(yin)此，可分(fen)(fen)別計算平(ping)衡凝(ning)固(gu)(gu)和(he)(he)Scheil凝(ning)固(gu)(gu)過程(cheng)(cheng)中(zhong)的(de)(de)(de)Aso、Ase和(he)(he)Pg,闡明實際(ji)凝(ning)固(gu)(gu)過程(cheng)(cheng)中(zhong)壓力等(deng)因(yin)素對(dui)氮(dan)氣(qi)泡形成的(de)(de)(de)影響規(gui)律(lv)。

  現以21.5Cr5Mn1.5Ni0.25N含氮雙(shuang)相(xiang)鋼D1鑄(zhu)錠為例，對(dui)凝固過程中Aso、Ase和P8的(de)變化趨勢(shi)進行計算。圖2-61描述了ΔAso(=Asa-Aso,0)和AAse(=Ase-Ase,o)隨固相(xiang)質量分(fen)數(shu)的(de)變化趨勢(shi)（Aso,0和Asc,0分(fen)別為D1鑄(zhu)錠凝固時Aso和Ase的(de)初始值）。

  在(zai)平衡凝(ning)固(gu)(gu)(gu)(gu)和Scheil凝(ning)固(gu)(gu)(gu)(gu)過(guo)(guo)(guo)(guo)程(cheng)(cheng)中(zhong)，ΔAso的(de)(de)最(zui)(zui)小(xiao)值分(fen)別為(wei)－0.145和－0.397,與(yu)此(ci)相(xiang)(xiang)對應(ying)(ying)的(de)(de)ΔAse值最(zui)(zui)大，分(fen)別為(wei)0.68和0.92.在(zai)整(zheng)個(ge)凝(ning)固(gu)(gu)(gu)(gu)過(guo)(guo)(guo)(guo)程(cheng)(cheng)中(zhong)，由于ΔAse與(yu)ΔAso之和始終大于零，因(yin)而(er)枝晶間殘余液相(xiang)(xiang)中(zhong)氮偏析對D1 鑄錠凝(ning)固(gu)(gu)(gu)(gu)過(guo)(guo)(guo)(guo)程(cheng)(cheng)中(zhong)氮氣(qi)泡(pao)(pao)形成的(de)(de)影(ying)(ying)響大于氮溶解度，起主導(dao)作(zuo)用(yong)。此(ci)外(wai)(wai)，在(zai)整(zheng)個(ge)凝(ning)固(gu)(gu)(gu)(gu)過(guo)(guo)(guo)(guo)程(cheng)(cheng)中(zhong)，P8變(bian)化趨勢如(ru)圖2-62所(suo)示，其變(bian)化規律與(yu)Young等(deng)。的(de)(de)研(yan)究(jiu)結果一(yi)致，Pg的(de)(de)最(zui)(zui)大值Pg與(yu)Ase+Aso的(de)(de)最(zui)(zui)大值相(xiang)(xiang)對應(ying)(ying)，且在(zai)平衡凝(ning)固(gu)(gu)(gu)(gu)和 Scheil 凝(ning)固(gu)(gu)(gu)(gu)過(guo)(guo)(guo)(guo)程(cheng)(cheng)中(zhong)分(fen)別為(wei)0.63MPa和0.62MPa.此(ci)外(wai)(wai)，可通過(guo)(guo)(guo)(guo)對比不同(tong)鑄錠中(zhong)的(de)(de)探討凝(ning)固(gu)(gu)(gu)(gu)壓力、初(chu)始氮質量分(fen)數以及(ji)合金元素（鉻(ge)和錳）等(deng)對液相(xiang)(xiang)中(zhong)氮氣(qi)泡(pao)(pao)形成的(de)(de)影(ying)(ying)響，進而(er)明晰各(ge)因(yin)素對氮氣(qi)孔形成的(de)(de)影(ying)(ying)響規律。