深冷处理对CF8M不锈钢微观组织和显微硬度的影响

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Abstract： This study explores microstructural evolution and microhardness changes CF8M staless steel before and after cryogenic treatment at -196∘C ，providg oretical and technical support for optimizg materials high-pressure seals and low-temperature valves for high-tech and commercial ships.Metalographic analysis， X-ray difractometer （XRD）analysis， microhardnesstestg，and nanodentation testg were used to asses phase composition，microstructure，and mechanical properties material.Results show that cryogenic treatment refes ferite morphology from blocky and network-like to lamelar or acicular，structural features characterized by tightly bonded gra boundaries and enhanced compositional uniformity with material. Meanwhile， XRD phaseanalysisrevealedpartial transformation austenite to martensite，leadg tocreased local hardness and a more uniform distribution.Nanodentation tests dicate reduced dentation depth post-treatment，reflectg improved plastic deformation resistanceand higher elastic modulus.This studyfers experimental and oretical sights for enhancg CF8M staless steel's cryogenic performance，advancg material design for extreme environments.

Keywords： cryogenic treatment; CF8M staless steel; microstructure; microhardness; nanodentation

1序言

CF8M铸造不锈钢（对应ASTMA351标准）是典型的铸造奥氏体不锈钢材料，具有优异的耐蚀性与力学性能，在高新船舶和民用船舶上获得广泛应用[1]。（剩余6636字）