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中南大学硕士学位论文 A390过共晶铝硅合金变质及热处理组织、性能研究姓名:林家平申请学位级别:硕士专业:材料学指导教师:肖于德 20090619
中南人学硕上学位论文
摘要
摘要
、、、变质处理的A390过共晶铝硅合金,通过力学性能测试、硬度测试、热膨胀系数测试、耐磨性分析、金相分析、XRD分析、SEM、TEM和EDS等方法研究了细化、变质处理对A390合金组织及性能变化的影响,并对其热处理制度进行了初步探讨。研究结果表明:
(1)P、P+La、
P+La+Sr及三联变质(P+La+)变质处理均可改
善A390合金的铸态组织,其中,经三联变质处理后,初晶硅变得均匀细小,长针状的共晶硅变成短杆状或点蠕状,相对未变质合金,%。(2)经过三联变质处理的A390合金的最优热处理工艺为500。C/4h固溶,水
淬后165℃/12h时效。
(3)铸造A390合金经细化、变质处理及热处理后,热膨胀系数减小,耐磨性得到改善,磨损率与摩擦系数都较未处理的合金要小。经过热处理后的三联变质处理A390合金具有优良的耐磨性能。
关键词:A390合金,变质处理,热处理工艺,耐磨性
Scientific Dissertation of Master Degree,CSU
ABSTRACT
AB STRACT
The A390 hypereutectic AI?Si
alloy samples were
was prepared
by
ingot
metallurgy method plex modification Was utilized during the
influence
of modification
on
microstructures,mechanical
properties
and
wear
properties of A390 alloy were
investigated
by
impact toughness test,hardness
measurement,coefficient of thermal expansion test,wear resistance test,OM,XRD,
SEM,TEM
and results
are
as following:
and
(1)Phosphorus
modification,phosphorus
complex
lanthanum
modification。
triple united
phosphorus,lanthanum and strontium
modification
and
complex modification Can improve
triple
the microstructure of A390
treated by declined
is almost
united
complex modification,the size of primary
silicon of A390
alloy
and
its distribution
became
at
long needle like eutectic
silicon
strength
room
temperature has been increased by %.
for 4 hours,quenching in water and then aged
(2)The
optimum heat treatment process for triple plex modified
A390 alloy is solid solution in 500"C
in 1 65。C for 1 0 this heat treatment process,the main
st