一、氮氣(qi)孔的形成機理

  在21.5Cr5Mn1.5Ni0.25N含氮(dan)(dan)(dan)(dan)(dan)(dan)雙相(xiang)(xiang)(xiang)(xiang)(xiang)鋼(gang)凝(ning)(ning)(ning)固(gu)過(guo)程(cheng)(cheng)(cheng)中(zhong)(zhong)(zhong)(zhong)，氮(dan)(dan)(dan)(dan)(dan)(dan)氣(qi)孔(kong)形(xing)成和(he)凝(ning)(ning)(ning)固(gu)前沿處［％N]1iq隨距離變(bian)化(hua)的(de)(de)(de)規律如圖2-55所(suo)(suo)示(shi)(shi)。由于糊狀(zhuang)區(qu)(qu)內大(da)量枝(zhi)晶(jing)(jing)網狀(zhuang)結構的(de)(de)(de)形(xing)成，液(ye)(ye)(ye)相(xiang)(xiang)(xiang)(xiang)(xiang)的(de)(de)(de)對流只(zhi)存(cun)在于一(yi)次枝(zhi)晶(jing)(jing)尖端位置附(fu)(fu)近。且枝(zhi)晶(jing)(jing)間幾乎無(wu)液(ye)(ye)(ye)相(xiang)(xiang)(xiang)(xiang)(xiang)的(de)(de)(de)流動。因(yin)此(ci)，枝(zhi)晶(jing)(jing)間殘余(yu)液(ye)(ye)(ye)相(xiang)(xiang)(xiang)(xiang)(xiang)中(zhong)(zhong)(zhong)(zhong)的(de)(de)(de)氮(dan)(dan)(dan)(dan)(dan)(dan)傳(chuan)質(zhi)主要(yao)依靠氮(dan)(dan)(dan)(dan)(dan)(dan)的(de)(de)(de)擴散行(xing)為，且糊狀(zhuang)區(qu)(qu)內氮(dan)(dan)(dan)(dan)(dan)(dan)傳(chuan)質(zhi)速(su)率(lv)非常小(xiao)。初始相(xiang)(xiang)(xiang)(xiang)(xiang)貧氮(dan)(dan)(dan)(dan)(dan)(dan)鐵(tie)素(su)(su)體(ti)(ti)相(xiang)(xiang)(xiang)(xiang)(xiang)8的(de)(de)(de)氮(dan)(dan)(dan)(dan)(dan)(dan)溶解(jie)(jie)度(du)和(he)糊狀(zhuang)區(qu)(qu)的(de)(de)(de)氮(dan)(dan)(dan)(dan)(dan)(dan)傳(chuan)質(zhi)速(su)率(lv)較(jiao)低，導致(zhi)在貧氮(dan)(dan)(dan)(dan)(dan)(dan)鐵(tie)素(su)(su)體(ti)(ti)相(xiang)(xiang)(xiang)(xiang)(xiang)枝(zhi)晶(jing)(jing)附(fu)(fu)近的(de)(de)(de)液(ye)(ye)(ye)相(xiang)(xiang)(xiang)(xiang)(xiang)中(zhong)(zhong)(zhong)(zhong)出現氮(dan)(dan)(dan)(dan)(dan)(dan)富(fu)(fu)集，且［％N]iq迅速(su)增大(da)，如圖2-55(a)所(suo)(suo)示(shi)(shi)。根據Yang和(he) Leel70]、Svyazhin 等(deng)、Ridolfi 和(he) Tassal的(de)(de)(de)報道可知，當［％N]iq的(de)(de)(de)最大(da)值超過(guo)氮(dan)(dan)(dan)(dan)(dan)(dan)氣(qi)泡(pao)形(xing)成的(de)(de)(de)臨界(jie)氮(dan)(dan)(dan)(dan)(dan)(dan)質(zhi)量分數(shu)（［％N]pore)時(shi)，該區(qu)(qu)域(yu)有氣(qi)泡(pao)形(xing)成的(de)(de)(de)可能(neng)性，如圖2-55(b)所(suo)(suo)示(shi)(shi)。在后(hou)續的(de)(de)(de)凝(ning)(ning)(ning)固(gu)過(guo)程(cheng)(cheng)(cheng)中(zhong)(zhong)(zhong)(zhong)，隨著包(bao)晶(jing)(jing)反應的(de)(de)(de)進行(xing)，富(fu)(fu)氮(dan)(dan)(dan)(dan)(dan)(dan)奧(ao)氏體(ti)(ti)相(xiang)(xiang)(xiang)(xiang)(xiang)γ以異質(zhi)形(xing)核(he)的(de)(de)(de)方式(shi)在鐵(tie)素(su)(su)體(ti)(ti)相(xiang)(xiang)(xiang)(xiang)(xiang)8枝(zhi)晶(jing)(jing)的(de)(de)(de)表(biao)(biao)面(mian)開始形(xing)核(he)長(chang)(chang)(chang)大(da)，逐(zhu)漸包(bao)裹鐵(tie)素(su)(su)體(ti)(ti)相(xiang)(xiang)(xiang)(xiang)(xiang)枝(zhi)晶(jing)(jing)表(biao)(biao)面(mian)，并開始捕獲殘余(yu)液(ye)(ye)(ye)相(xiang)(xiang)(xiang)(xiang)(xiang)中(zhong)(zhong)(zhong)(zhong)的(de)(de)(de)氮(dan)(dan)(dan)(dan)(dan)(dan)氣(qi)泡(pao)，對比(bi)圖2-51和(he)圖2-56可知，此(ci)時(shi)枝(zhi)晶(jing)(jing)間殘余(yu)［％N]1ig的(de)(de)(de)增長(chang)(chang)(chang)速(su)率(lv)減小(xiao)。對平衡(heng)凝(ning)(ning)(ning)固(gu)而言(yan)，殘余(yu)液(ye)(ye)(ye)相(xiang)(xiang)(xiang)(xiang)(xiang)中(zhong)(zhong)(zhong)(zhong)氮(dan)(dan)(dan)(dan)(dan)(dan)氣(qi)泡(pao)形(xing)成以后(hou)，氮(dan)(dan)(dan)(dan)(dan)(dan)的(de)(de)(de)富(fu)(fu)集程(cheng)(cheng)(cheng)度(du)減弱，［％N]1iq增長(chang)(chang)(chang)速(su)率(lv)的(de)(de)(de)減小(xiao)程(cheng)(cheng)(cheng)度(du)明顯；相(xiang)(xiang)(xiang)(xiang)(xiang)比(bi)之下，Scheil凝(ning)(ning)(ning)固(gu)過(guo)程(cheng)(cheng)(cheng)中(zhong)(zhong)(zhong)(zhong)，氮(dan)(dan)(dan)(dan)(dan)(dan)氣(qi)泡(pao)形(xing)成以后(hou)，殘余(yu)液(ye)(ye)(ye)相(xiang)(xiang)(xiang)(xiang)(xiang)中(zhong)(zhong)(zhong)(zhong)氮(dan)(dan)(dan)(dan)(dan)(dan)富(fu)(fu)集狀(zhuang)態有所(suo)(suo)緩(huan)解(jie)(jie)，但幅(fu)度(du)很小(xiao)。隨著凝(ning)(ning)(ning)固(gu)界(jie)面(mian)的(de)(de)(de)進一(yi)步(bu)推移，被(bei)捕獲的(de)(de)(de)氮(dan)(dan)(dan)(dan)(dan)(dan)氣(qi)泡(pao)在奧(ao)氏體(ti)(ti)相(xiang)(xiang)(xiang)(xiang)(xiang)表(biao)(biao)面(mian)開始長(chang)(chang)(chang)大(da)，并沿凝(ning)(ning)(ning)固(gu)方向拉長(chang)(chang)(chang)，如圖2-55(c)所(suo)(suo)示(shi)(shi)。

  氮氣孔(kong)沿徑向(xiang)生長，生長方(fang)向(xiang)與凝(ning)固(gu)方(fang)向(xiang)一(yi)致，那(nei)么(me)氮氣孔(kong)初始(shi)形成(cheng)位(wei)置(zhi)(zhi)靠(kao)近鑄錠邊(bian)部，且氮氣泡初始(shi)位(wei)置(zhi)(zhi)邊(bian)緣(yuan)全由奧氏體(ti)相γ構成(cheng)（圖(tu)2-57中I區），與圖(tu)2-55描述相符。隨著氮氣孔(kong)被拉長，鐵素體(ti)相和奧氏體(ti)相以體(ti)積分數比約(yue)為0.92的(de)(de)關系交(jiao)替在氮氣泡周圍形成(cheng)，直到氮氣孔(kong)閉(bi)合。凝(ning)固(gu)結束后(hou)，氮氣孔(kong)的(de)(de)宏(hong)觀形貌類(lei)似于橢圓形，與Wei等的(de)(de)研究結果一(yi)致

二(er)、氮(dan)微觀偏析對氮(dan)氣孔的影響

  氮(dan)(dan)的(de)分(fen)配系數(shu)較小，導致液相(xiang)(xiang)(xiang)向(xiang)固(gu)相(xiang)(xiang)(xiang)轉變的(de)過程(cheng)中(zhong)(zhong)(zhong)，固(gu)相(xiang)(xiang)(xiang)會將多余的(de)氮(dan)(dan)轉移到殘(can)(can)余液相(xiang)(xiang)(xiang)中(zhong)(zhong)(zhong)，形成(cheng)氮(dan)(dan)偏析(xi)。在氮(dan)(dan)偏析(xi)程(cheng)度(du)(du)逐(zhu)漸加重(zhong)(zhong)的(de)過程(cheng)中(zhong)(zhong)(zhong)，當殘(can)(can)余液相(xiang)(xiang)(xiang)中(zhong)(zhong)(zhong)氮(dan)(dan)質量分(fen)數(shu)超過其飽和度(du)(du)時(shi)(shi)，極易形成(cheng)氮(dan)(dan)氣(qi)泡。隨(sui)著凝(ning)固(gu)的(de)進行(xing)(xing)，若氣(qi)泡無(wu)法上浮而被捕獲，凝(ning)固(gu)結束后就會在鑄錠內部(bu)形成(cheng)氣(qi)孔。因(yin)(yin)此，凝(ning)固(gu)過程(cheng)中(zhong)(zhong)(zhong)氮(dan)(dan)偏析(xi)和溶解度(du)(du)對鑄錠中(zhong)(zhong)(zhong)最終氮(dan)(dan)氣(qi)孔的(de)形成(cheng)有至關(guan)重(zhong)(zhong)要的(de)作用。氮(dan)(dan)氣(qi)孔多數(shu)情況下與(yu)疏松縮孔共(gong)存，內壁凹凸不(bu)平呈現裂紋狀，且(qie)整(zheng)個氣(qi)孔形狀不(bu)規則，如圖2-58所示。此類氣(qi)孔不(bu)僅與(yu)鋼液中(zhong)(zhong)(zhong)氣(qi)泡的(de)形成(cheng)有關(guan)，還受凝(ning)固(gu)收縮等因(yin)(yin)素(su)的(de)影響，且(qie)多數(shu)分(fen)布于鑄錠心(xin)部(bu)，尤(you)其在中(zhong)(zhong)(zhong)心(xin)等軸晶(jing)區。這主要由于中(zhong)(zhong)(zhong)心(xin)等軸晶(jing)區內枝晶(jing)生長(chang)較發達(da)，容易形成(cheng)復(fu)雜的(de)網狀結構，從而將液相(xiang)(xiang)(xiang)分(fen)割成(cheng)無(wu)數(shu)個獨立的(de)液相(xiang)(xiang)(xiang)區域(yu)，當發生凝(ning)固(gu)收縮時(shi)(shi)，難以進行(xing)(xing)補縮，在形成(cheng)疏松縮孔的(de)同(tong)時(shi)(shi)，局(ju)部(bu)鋼液靜壓力降低(di)，促使氮(dan)(dan)從殘(can)(can)余液相(xiang)(xiang)(xiang)中(zhong)(zhong)(zhong)析(xi)出，從而形成(cheng)了(le)氮(dan)(dan)氣(qi)孔和疏松縮孔共(gong)存的(de)宏觀缺陷(xian)。

  平衡凝固(gu)時，19Cr14Mn0.9N含氮(dan)(dan)奧氏(shi)體(ti)(ti)不銹(xiu)鋼(gang)殘余液(ye)相(xiang)中氮(dan)(dan)偏析與(yu)體(ti)(ti)系氮(dan)(dan)溶解度(du)的(de)(de)差(cha)值如圖2-59所示。凝固(gu)初期鐵素體(ti)(ti)阱（ferrite trap)的(de)(de)形(xing)(xing)成(cheng)，導(dao)致氮(dan)(dan)溶解度(du)的(de)(de)降(jiang)低，進而使(shi)氮(dan)(dan)偏析與(yu)體(ti)(ti)系氮(dan)(dan)溶解度(du)差(cha)值呈(cheng)現出略微增大的(de)(de)趨勢。但在后續(xu)凝固(gu)過程中，隨著鐵素體(ti)(ti)阱的(de)(de)消失(shi)以及富氮(dan)(dan)奧氏(shi)體(ti)(ti)相(xiang)的(de)(de)不斷(duan)形(xing)(xing)成(cheng)，差(cha)值減(jian)小；在整個(ge)凝固(gu)過程中差(cha)值始終(zhong)較小，且變化(hua)幅(fu)度(du)較窄。對于19Cr14Mn0.9N 含氮(dan)(dan)奧氏(shi)體(ti)(ti)不銹(xiu)鋼(gang)，液(ye)相(xiang)中氮(dan)(dan)氣泡的(de)(de)形(xing)(xing)成(cheng)趨勢較小，難以在鑄錠內(nei)形(xing)(xing)成(cheng)獨立內(nei)壁光滑的(de)(de)規則(ze)氮(dan)(dan)氣孔。

  此外，目(mu)前(qian)有人對奧(ao)氏(shi)(shi)體(ti)鋼(gang)(gang)凝(ning)固(gu)(gu)(gu)過程(cheng)中(zhong)(zhong)氮(dan)(dan)(dan)(dan)(dan)氣(qi)孔(kong)的(de)形(xing)(xing)成進行了(le)大(da)量研究(jiu)，如Yang和(he)(he)Leel901研究(jiu)了(le)奧(ao)氏(shi)(shi)體(ti)鋼(gang)(gang)16Cr3NixMn(x=9和(he)(he)11)凝(ning)固(gu)(gu)(gu)過程(cheng)中(zhong)(zhong)壓(ya)力和(he)(he)初(chu)始氮(dan)(dan)(dan)(dan)(dan)質量分數等因(yin)素對氮(dan)(dan)(dan)(dan)(dan)氣(qi)孔(kong)形(xing)(xing)成的(de)影響(xiang)規(gui)(gui)律，并建立(li)了(le)相(xiang)(xiang)應(ying)的(de)預測模(mo)型。Ridolfi和(he)(he)Tassal[84]分析了(le)氮(dan)(dan)(dan)(dan)(dan)偏(pian)析、合金(jin)元(yuan)素、冷卻速(su)率(lv)以及(ji)枝晶間(jian)距(ju)對奧(ao)氏(shi)(shi)體(ti)鋼(gang)(gang)中(zhong)(zhong)氮(dan)(dan)(dan)(dan)(dan)氣(qi)孔(kong)的(de)影響(xiang)規(gui)(gui)律，并揭示了(le)奧(ao)氏(shi)(shi)體(ti)鋼(gang)(gang)中(zhong)(zhong)氮(dan)(dan)(dan)(dan)(dan)氣(qi)孔(kong)形(xing)(xing)成機理。然而，目(mu)前(qian)對于雙(shuang)相(xiang)(xiang)鋼(gang)(gang)中(zhong)(zhong)氮(dan)(dan)(dan)(dan)(dan)氣(qi)孔(kong)形(xing)(xing)成的(de)研究(jiu)較(jiao)少，且主要集中(zhong)(zhong)在(zai)(zai)合金(jin)元(yuan)素、鑄造方式、冷卻速(su)率(lv)等因(yin)素對氮(dan)(dan)(dan)(dan)(dan)氣(qi)孔(kong)影響(xiang)規(gui)(gui)律的(de)研究(jiu)，鮮(xian)有對雙(shuang)相(xiang)(xiang)鋼(gang)(gang)中(zhong)(zhong)氮(dan)(dan)(dan)(dan)(dan)氣(qi)孔(kong)形(xing)(xing)成機理的(de)報道。以21.5Cr5Mn1.5Ni0.25N含(han)氮(dan)(dan)(dan)(dan)(dan)雙(shuang)相(xiang)(xiang)鋼(gang)(gang)為例，氮(dan)(dan)(dan)(dan)(dan)偏(pian)析與溶解度的(de)差(cha)值在(zai)(zai)整個凝(ning)固(gu)(gu)(gu)過程(cheng)中(zhong)(zhong)的(de)變化趨勢，如圖2-59所示。隨著(zhu)凝(ning)固(gu)(gu)(gu)的(de)進行，氮(dan)(dan)(dan)(dan)(dan)偏(pian)析始終大(da)于氮(dan)(dan)(dan)(dan)(dan)溶解度，且差(cha)值呈現出快速(su)增大(da)的(de)趨勢。因(yin)此，在(zai)(zai)21.5Cr5Mn1.5Ni0.25N 含(han)氮(dan)(dan)(dan)(dan)(dan)雙(shuang)相(xiang)(xiang)鋼(gang)(gang)凝(ning)固(gu)(gu)(gu)過程(cheng)中(zhong)(zhong)，氮(dan)(dan)(dan)(dan)(dan)偏(pian)析嚴(yan)重，殘(can)余(yu)液相(xiang)(xiang)內(nei)氮(dan)(dan)(dan)(dan)(dan)氣(qi)泡(pao)形(xing)(xing)成趨勢較(jiao)大(da)，明顯高于19Cr14Mn0.9N含(han)氮(dan)(dan)(dan)(dan)(dan)奧(ao)氏(shi)(shi)體(ti)不(bu)銹鋼(gang)(gang)。

  氮氣(qi)(qi)泡(pao)(pao)形成和(he)(he)長大具有重要的作(zuo)用(yong)(yong)（圖2-60).其中，σ為氣(qi)(qi)液界面(mian)的表面(mian)張力，r為氣(qi)(qi)泡(pao)(pao)半徑(jing)。結合(he)經典(dian)形核(he)理(li)論(lun)，氮氣(qi)(qi)泡(pao)(pao)在(zai)鋼液中穩定存在(zai)的必(bi)要條件為氣(qi)(qi)泡(pao)(pao)內壓力大于作(zuo)用(yong)(yong)于氣(qi)(qi)泡(pao)(pao)的所(suo)有壓力之和(he)(he)，即

  式中，Aso由凝固(gu)過程中除(chu)氮(dan)(dan)以外其(qi)他合(he)金元(yuan)素(su)的(de)(de)(de)微觀偏(pian)(pian)析進行計算(suan)，其(qi)值隨(sui)著枝(zhi)晶間(jian)(jian)(jian)殘余液(ye)相中氮(dan)(dan)溶解度(du)的(de)(de)(de)增加而減小，表征了(le)枝(zhi)晶間(jian)(jian)(jian)殘余液(ye)相中氮(dan)(dan)溶解度(du)對(dui)氮(dan)(dan)氣泡形成(cheng)的(de)(de)(de)影響(xiang)程度(du)；Ase表征了(le)枝(zhi)晶間(jian)(jian)(jian)氮(dan)(dan)偏(pian)(pian)析對(dui)氮(dan)(dan)氣泡形成(cheng)的(de)(de)(de)影響(xiang)程度(du)，可由凝固(gu)過程中枝(zhi)晶間(jian)(jian)(jian)殘余液(ye)相中氮(dan)(dan)偏(pian)(pian)析計算(suan)獲得(de)，其(qi)值隨(sui)著氮(dan)(dan)偏(pian)(pian)析的(de)(de)(de)增大而增大。此外，用于(yu)計算(suan)Aso和(he)Ase時所需的(de)(de)(de)合(he)金元(yuan)素(su)偏(pian)(pian)析均由鋼凝固(gu)相變所致。

  氮(dan)氣(qi)(qi)泡的(de)(de)形(xing)(xing)核和(he)長大過(guo)(guo)(guo)程復(fu)雜(za)，且影響因(yin)素眾多，包括凝(ning)(ning)固(gu)(gu)收縮、冶煉環境以及坩堝材(cai)質(zhi)等。因(yin)此，很難采用(yong)Pg值(zhi)精確預測凝(ning)(ning)固(gu)(gu)過(guo)(guo)(guo)程中(zhong)(zhong)氮(dan)氣(qi)(qi)泡的(de)(de)形(xing)(xing)成(cheng)和(he)長大。然而基(ji)于Yang等的(de)(de)實(shi)(shi)驗研究［70,77],在評估凝(ning)(ning)固(gu)(gu)壓(ya)力、合金成(cheng)分等因(yin)素對氮(dan)氣(qi)(qi)泡形(xing)(xing)成(cheng)的(de)(de)影響程度(du)時，Pg起關鍵作用(yong)。實(shi)(shi)際凝(ning)(ning)固(gu)(gu)過(guo)(guo)(guo)程介于平衡凝(ning)(ning)固(gu)(gu)（固(gu)(gu)／液相(xiang)中(zhong)(zhong)溶質(zhi)完全擴(kuo)散(san)(san)）和(he)Scheil凝(ning)(ning)固(gu)(gu)（固(gu)(gu)相(xiang)無溶質(zhi)擴(kuo)散(san)(san)，液相(xiang)中(zhong)(zhong)完全擴(kuo)散(san)(san)）之間70].因(yin)此，可分別計算平衡凝(ning)(ning)固(gu)(gu)和(he)Scheil凝(ning)(ning)固(gu)(gu)過(guo)(guo)(guo)程中(zhong)(zhong)的(de)(de)Aso、Ase和(he)Pg,闡明實(shi)(shi)際凝(ning)(ning)固(gu)(gu)過(guo)(guo)(guo)程中(zhong)(zhong)壓(ya)力等因(yin)素對氮(dan)氣(qi)(qi)泡形(xing)(xing)成(cheng)的(de)(de)影響規律。

  現(xian)以21.5Cr5Mn1.5Ni0.25N含氮雙相鋼D1鑄(zhu)錠為(wei)例，對凝(ning)固過程中Aso、Ase和(he)P8的變(bian)化趨(qu)勢進行計算(suan)。圖2-61描述了ΔAso(=Asa-Aso,0)和(he)AAse(=Ase-Ase,o)隨固相質(zhi)量分數的變(bian)化趨(qu)勢（Aso,0和(he)Asc,0分別(bie)為(wei)D1鑄(zhu)錠凝(ning)固時Aso和(he)Ase的初始值）。

  在(zai)平衡(heng)凝(ning)(ning)(ning)固(gu)(gu)(gu)和(he)(he)Scheil凝(ning)(ning)(ning)固(gu)(gu)(gu)過(guo)(guo)程中(zhong)(zhong)，ΔAso的(de)最(zui)(zui)(zui)小值分別為(wei)－0.145和(he)(he)－0.397,與(yu)此相對(dui)(dui)應的(de)ΔAse值最(zui)(zui)(zui)大(da)，分別為(wei)0.68和(he)(he)0.92.在(zai)整(zheng)個(ge)凝(ning)(ning)(ning)固(gu)(gu)(gu)過(guo)(guo)程中(zhong)(zhong)，由于ΔAse與(yu)ΔAso之和(he)(he)始(shi)終大(da)于零，因而枝晶間殘余(yu)液(ye)相中(zhong)(zhong)氮偏析對(dui)(dui)D1 鑄(zhu)錠凝(ning)(ning)(ning)固(gu)(gu)(gu)過(guo)(guo)程中(zhong)(zhong)氮氣(qi)泡形(xing)(xing)成(cheng)的(de)影響大(da)于氮溶解度，起主導作用(yong)。此外(wai)(wai)，在(zai)整(zheng)個(ge)凝(ning)(ning)(ning)固(gu)(gu)(gu)過(guo)(guo)程中(zhong)(zhong)，P8變化趨勢如圖2-62所示，其變化規(gui)律與(yu)Young等。的(de)研(yan)究結(jie)果一致(zhi)，Pg的(de)最(zui)(zui)(zui)大(da)值Pg與(yu)Ase+Aso的(de)最(zui)(zui)(zui)大(da)值相對(dui)(dui)應，且在(zai)平衡(heng)凝(ning)(ning)(ning)固(gu)(gu)(gu)和(he)(he) Scheil 凝(ning)(ning)(ning)固(gu)(gu)(gu)過(guo)(guo)程中(zhong)(zhong)分別為(wei)0.63MPa和(he)(he)0.62MPa.此外(wai)(wai)，可通過(guo)(guo)對(dui)(dui)比不同鑄(zhu)錠中(zhong)(zhong)的(de)探(tan)討凝(ning)(ning)(ning)固(gu)(gu)(gu)壓(ya)力、初始(shi)氮質量分數以(yi)及(ji)合金(jin)元素（鉻和(he)(he)錳）等對(dui)(dui)液(ye)相中(zhong)(zhong)氮氣(qi)泡形(xing)(xing)成(cheng)的(de)影響，進(jin)而明晰各因素對(dui)(dui)氮氣(qi)孔(kong)形(xing)(xing)成(cheng)的(de)影響規(gui)律。