大部分常用鎳鉻系奧(ao)氏體不銹鋼自高溫奧氏體狀態冷至室溫獲得的奧氏體基體組織都是亞穩定的，當繼續冷卻到室溫以下更低的溫度，或者經受冷變形，其中的一部分或大部分奧氏體會發生馬氏體轉變，變成馬氏體組織。不銹鋼中馬氏體有兩種形態：體心立方的a'馬氏體，呈鐵磁性；六方結構的ε馬氏體，為非鐵磁性。由于ε馬氏體總是與a'馬氏體伴隨而出現，有人認為ε馬氏體是γ→a＇過程中的一種過渡相，也有人認為ε馬氏體是一種獨立相。

 馬氏體轉變受鋼的化(hua)學成分(fen)、溫度、冷變形(xing)量(liang)及變形(xing)速率的影響。

  曾對不同成(cheng)(cheng)分(fen)的(de)(de)Fe-Mn-Cr-Ni合(he)金的(de)(de)馬氏(shi)體(ti)相(xiang)(xiang)(xiang)(xiang)(xiang)(xiang)變(bian)(bian)(bian)(bian)(bian)進行過(guo)研(yan)究（含0.03％C、0.01％～0.03％Si、0.006％～0.019％N、0.012％～0.10％Al）：含20％Mn的(de)(de)Fe-Mn合(he)金自(zi)1050℃水冷(leng)(leng)(leng)(leng)(leng)(leng)至(zhi)(zhi)室(shi)(shi)(shi)溫(wen)(wen)，發(fa)生(sheng)(sheng)(sheng)γ→E轉(zhuan)(zhuan)變(bian)(bian)(bian)(bian)(bian)，相(xiang)(xiang)(xiang)(xiang)(xiang)(xiang)約(yue)(yue)為(wei)(wei)(wei)40％，再冷(leng)(leng)(leng)(leng)(leng)(leng)卻至(zhi)(zhi)-196℃，y相(xiang)(xiang)(xiang)(xiang)(xiang)(xiang)幾乎全部轉(zhuan)(zhuan)變(bian)(bian)(bian)(bian)(bian)為(wei)(wei)(wei)ε相(xiang)(xiang)(xiang)(xiang)(xiang)(xiang)，只生(sheng)(sheng)(sheng)成(cheng)(cheng)少量的(de)(de)α'相(xiang)(xiang)(xiang)(xiang)(xiang)(xiang)。成(cheng)(cheng)分(fen)為(wei)(wei)(wei)Fe-5％Mn-15％Cr-9％Ni合(he)金自(zi)1050℃水冷(leng)(leng)(leng)(leng)(leng)(leng)至(zhi)(zhi)室(shi)(shi)(shi)溫(wen)(wen)，10min后(hou)冷(leng)(leng)(leng)(leng)(leng)(leng)至(zhi)(zhi)-196℃，不發(fa)生(sheng)(sheng)(sheng)馬氏(shi)體(ti)相(xiang)(xiang)(xiang)(xiang)(xiang)(xiang)變(bian)(bian)(bian)(bian)(bian)，仍為(wei)(wei)(wei)100％的(de)(de)y相(xiang)(xiang)(xiang)(xiang)(xiang)(xiang)；冷(leng)(leng)(leng)(leng)(leng)(leng)至(zhi)(zhi)室(shi)(shi)(shi)溫(wen)(wen)，再在20℃下(xia)(xia)施以(yi)40％冷(leng)(leng)(leng)(leng)(leng)(leng)變(bian)(bian)(bian)(bian)(bian)形(xing)，將發(fa)生(sheng)(sheng)(sheng)γ→ε＋α＇的(de)(de)轉(zhuan)(zhuan)變(bian)(bian)(bian)(bian)(bian)，轉(zhuan)(zhuan)變(bian)(bian)(bian)(bian)(bian)量約(yue)(yue)為(wei)(wei)(wei)20％，其中(zhong)約(yue)(yue)2/3為(wei)(wei)(wei)ε相(xiang)(xiang)(xiang)(xiang)(xiang)(xiang)，1/3為(wei)(wei)(wei)α＇相(xiang)(xiang)(xiang)(xiang)(xiang)(xiang)；如(ru)果(guo)自(zi)1050℃水冷(leng)(leng)(leng)(leng)(leng)(leng)至(zhi)(zhi)室(shi)(shi)(shi)溫(wen)(wen)后(hou)，再在-196℃下(xia)(xia)施以(yi)40％的(de)(de)冷(leng)(leng)(leng)(leng)(leng)(leng)變(bian)(bian)(bian)(bian)(bian)形(xing)，發(fa)生(sheng)(sheng)(sheng)γ→e＋α'的(de)(de)轉(zhuan)(zhuan)變(bian)(bian)(bian)(bian)(bian)，轉(zhuan)(zhuan)變(bian)(bian)(bian)(bian)(bian)量近90％，其中(zhong)約(yue)(yue)1/4為(wei)(wei)(wei)ε相(xiang)(xiang)(xiang)(xiang)(xiang)(xiang)，3/4為(wei)(wei)(wei)a'相(xiang)(xiang)(xiang)(xiang)(xiang)(xiang)。成(cheng)(cheng)分(fen)為(wei)(wei)(wei)Fe-20％Cr-12％Ni的(de)(de)合(he)金自(zi)1050℃水冷(leng)(leng)(leng)(leng)(leng)(leng)，10min后(hou)冷(leng)(leng)(leng)(leng)(leng)(leng)至(zhi)(zhi)-196℃，不發(fa)生(sheng)(sheng)(sheng)馬氏(shi)體(ti)相(xiang)(xiang)(xiang)(xiang)(xiang)(xiang)變(bian)(bian)(bian)(bian)(bian)，冷(leng)(leng)(leng)(leng)(leng)(leng)至(zhi)(zhi)室(shi)(shi)(shi)溫(wen)(wen)在20℃下(xia)(xia)施以(yi)40％的(de)(de)冷(leng)(leng)(leng)(leng)(leng)(leng)變(bian)(bian)(bian)(bian)(bian)形(xing)，僅發(fa)生(sheng)(sheng)(sheng)γ→E轉(zhuan)(zhuan)變(bian)(bian)(bian)(bian)(bian)，相(xiang)(xiang)(xiang)(xiang)(xiang)(xiang)約(yue)(yue)為(wei)(wei)(wei)10％；如(ru)果(guo)冷(leng)(leng)(leng)(leng)(leng)(leng)至(zhi)(zhi)室(shi)(shi)(shi)溫(wen)(wen)后(hou)再在-196℃下(xia)(xia)施以(yi)40％的(de)(de)冷(leng)(leng)(leng)(leng)(leng)(leng)變(bian)(bian)(bian)(bian)(bian)形(xing)，將發(fa)生(sheng)(sheng)(sheng)γ→ε＋α轉(zhuan)(zhuan)變(bian)(bian)(bian)(bian)(bian)，轉(zhuan)(zhuan)變(bian)(bian)(bian)(bian)(bian)量約(yue)(yue)為(wei)(wei)(wei)55％，15％為(wei)(wei)(wei)ε相(xiang)(xiang)(xiang)(xiang)(xiang)(xiang)，40％為(wei)(wei)(wei)α'相(xiang)(xiang)(xiang)(xiang)(xiang)(xiang)。

對于(yu)奧氏體(ti)不銹鋼的(de)(de)馬氏體(ti)轉變的(de)(de)臨界溫度M3，已建立起若干Ms，點(dian)（a'）與合金成分關(guan)系的(de)(de)經驗公(gong)式，下面是其中的(de)(de)一(yi)個(ge)表達式：

  上面兩個公式說明，奧氏體(ti)不(bu)銹鋼中合金元素含量越(yue)高，馬氏體(ti)點就(jiu)越(yue)低，馬氏體(ti)轉(zhuan)變就(jiu)越(yue)不(bu)容(rong)易發生。

   在18Cr-8Ni奧氏體不銹鋼中，α'馬氏體形成量隨冷變形量加大和變形溫度降低而增多，如圖9.46和圖9.47所示。可以看出，在每一變形溫度下，α'馬氏體含量隨冷變形量加大而增長到一定數值后將趨于飽和。隨變形溫度的降低，在同樣變形量的條件下，α'馬氏體的生成量增加，其增加也有一個飽和值，亦即無論采取什么措施，不可能完全轉變為馬氏體。這種奧氏體穩定化受多種因素影響，除合金成分和晶粒度等內在因素外，還有奧氏體化溫度、冷卻速率等外界因素。

 變(bian)形(xing)速率對(dui)馬(ma)氏體轉(zhuan)變(bian)的(de)影(ying)響主要(yao)是變(bian)形(xing)發(fa)熱導致材(cai)料溫(wen)(wen)度(du)上升的(de)作用，即變(bian)形(xing)速率越高，材(cai)料溫(wen)(wen)度(du)也越高，因而α'馬(ma)氏體的(de)生成量也越少。