共查询到20条相似文献,搜索用时 156 毫秒
1.
2.
研究了Fe-1.85C-8.03Cr-3.55Mn亚稳奥氏体基铸造合金的摩擦磨损表层特性,在较低的摩擦应力作用下,表层即可应变诱发α和ε马氏体。马氏体转变量随奥氏体形变量增加而增大,硬度也提高。由原奥氏体引起的表面硬度提高的原因:α和ε马氏体的形成;产生大量的位错和层错。在滑动磨损试验时,该合金的耐磨性高于25%Cr马氏体基白口铸铁。 相似文献
3.
随着航空航天和交通运输等领域对材料性能的要求日益严格,高体积分数陶瓷增强金属复合材料成为一种发展需求.基于激光增材制造原位成型多组分材料的优势,采用选区激光熔化(SLM)制备了15% SiC(体积分数)陶瓷增强马氏体时效钢(MS)复合材料(MMC).着重针对SiC与金属基体之间的相容性和开裂问题,从多个方面研究了SLM成型过程中的裂纹缺陷抑制措施,包括激光重熔、预热基板、设计支撑与成型方向;提高基体预热温度能够显著减少裂纹数量.同时,研究了SiC陶瓷对微观组织、相结构与相转变和硬度的影响及其与开裂的联系.MMC微观组织为带状组织和粗化的树枝晶组织,还存在富Si元素区域.MS中主要为马氏体相,添加SiC促进了奥氏体转变,使得MMC中主要为奥氏体相,树枝晶间仍可发现少量马氏体相.树枝晶主要为大角度晶界,表明MMC中形成了大量的位错.此外,加入高体积分数SiC后,基体材料的硬度得到明显提升. 相似文献
4.
本文应用亚稳态奥氏体不锈钢深冷滚压变形诱发马氏体和时效处理来制造紧固件,齿尖和齿根的硬度显著提高。金相研究发现:齿尖的组织是等轴晶粒,齿根是纤维状组织。电镜和X射线衍射分析认为硬度的提高是由于深冷滚压形诱发马氏体转变所致。从而为高强度紧固件的制造开辟了一条新的途径。 相似文献
5.
含钒耐磨堆焊合金的组织与性能 总被引:1,自引:0,他引:1
通过在Fe-Cr-C自保护金属芯堆焊焊丝中加入不同含量的钒(钒的质量分数分别为0.73%,2.3%,3.1%,4.1%),研究了钒对Fe-Cr-C堆焊合金微观组织、硬度及耐磨性的影响。试验结果表明,随钒含量的增加,堆焊合金组织的基体由奥氏体向奥氏体+马氏体转变,当钒的质量分数超过4%时,基体组织全部转变为马氏体;随钒含量的增加,堆焊合金组织中的初生碳化物由长条状、粗大直边六角状转变为球状或不规则形状,基体中析出大量弥散分布的二次碳化物;随钒含量的增加,堆焊合金的硬度和耐磨性亦相应提高。 相似文献
6.
本文对铁素体加马氏体及奥氏体加马氏两类双相钢中软相(铁素体、奥氏体)的相硬化及硬相(马氏体)的相软化现象进行了研究。结果表明,软相的硬化与硬相的软化是双相钢中普遍存在的现象。在铁素体-马氏体双相钢中,铁素体相硬化的原因是,奥氏体向马氏体转变时由于体积效应致使铁素体产生塑性变形,造成较高的位错密度,从而提高了硬度。马氏体相软化的原因较为复杂;双相钢中马氏体内孪晶数量较相同含碳量的单相马氏体为少;马氏体靠近铁素体处位错密度偏低;在马氏岛内存在一些不规则形状的铁素体微区,也是造成马氏体实测硬度偏低的一个原因。 相似文献
7.
Cr12MOV钢的隐晶马氏体及其强韧化 总被引:2,自引:0,他引:2
文章对Cr12MoV 钢的隐晶码氏体及其强韧化进行了研究。电镜分析表明,Cr12MoV 钢的淬火隐晶马氏体的微观形态与亚结构随淬火奥氏体化温度不同而异。950℃及其以下奥氏体化温度淬火,可获得单一的板条状位错融隐晶马氏体;而经950~1100℃奥氏体化温度淬火,则获得了由针(片)状孪晶马氏体与板条状位错马氏体构成的混合隐晶马氏体组织,并且孪晶马氏体随奥氏体化温度升高而增多。经机械性能试验发现,隐晶马氏体的微观形态与亚结构对钢的强韧性有直接影响。因此,为了使Cr12MoV 钢得到最有效的强韧化效果,不仅要均匀化和细化钢中的碳化物,而且要控制钢中隐晶马氏体的微观形态与亚结构。 相似文献
8.
9.
10.
Fe—C—Cr—Ni亚称奥氏体基合金的摩擦磨损表层特性 总被引:5,自引:1,他引:4
对Fe-1,9C-16.5Cr-2.6Ni亚稳奥氏体基合金在不同试验条件下的摩擦磨损表面研究表明,在较低的摩擦应力作用下,表层即可应变诱发α′和ε马体体。马氏体转变量随原奥氏体形变量增加而增大,硬度也增高。由原奥氏体引起的表面硬度提高的原因:(1)α′和ε马氏体的形成;(2)产生大量的位错和层错。在滑动磨损试验时,该合金的耐磨性高于25%Cr-马氏体基白口铸铁。 相似文献
11.
It has been established that the superelastic effect of TiNi alloy is related to a reversible martensitic transformation; that is, stress-induced transformation. The high elastic recovery of TiNi alloy has made it a potential candidate for high wear resistance applications. In the present study the tribological behavior of superelastic TiNi alloy was studied and compared to Ni, Ti, and AISI 304 stainless steel using dry sliding wear and friction tests. The effect of normal load and testing temperature on superelasticity has been investigated. It has been found that although AISI 304 stainless steel and superelastic TiNi alloy have similar hardness, TiNi exhibits superior wear resistance. The wear rate of AISI 304 stainless steel is over four times higher than TiNi. The superior wear resistance of TiNi and the effect of load and temperature on wear were discussed and related to the reversible martensitic phase transformation, as well as self-accommodation and stabilization of martensite. 相似文献
12.
A theoretical comparison of two possible shape memory processes in shape memory alloy reinforced metal matrix composite 总被引:1,自引:0,他引:1
Two possible shape memory processes, austenite to detwinned martensite transformation and twinned martensite to detwinned
martensite transformation of a shape memory alloy have been modeled and examined. Eshelby’s equivalent inclusion method with
Mori-Tanaka’s mean field theory is used for modeling of the shape memory processes of TiNi shape memory alloy reinforced aluminum
matrix composite. The shape memory amount of shape memory alloy, plastic strain and residual stress in the matrix are computed
and compared for the two processes. It is shown that the shape memory amount shows differences in a small prestrain region,
but the plastic strain and the residual stress in the matrix show differences in the whole prestrain region. The shape memory
process with initially martensitic state of the shape memory alloy would be favorable to the increase in the yield stress
of the composite owing to the targe compressive residual stress and plastic strain in the matrix. 相似文献
13.
14.
15.
TiNi形状记忆合金与不锈钢钎焊接头的微观组织与性能 总被引:3,自引:0,他引:3
采用含Ag50%~68%、Cu10%~30%、Zn12%~20%、Sn0%~10%的银基钎料,通过激光钎焊,改变钎焊 有效热输入(激光输出功率和钎焊时间),研究了TiNi形状记忆合金与不锈钢异质钎焊接头的微观组织和性能。结 果表明:AgCuZnSn钎料对TiNi形状记忆合金和不锈钢的润湿性较好,钎焊接头界面平整、致密,与TiNi形状记 忆合金形成的界面反应层较窄,而与不锈钢形成的界面反应层较宽。钎焊有效热输入对TiNi形状记忆合金热影响 区组织和性能影响较大。钎焊有效热输入量过高,将导致TiNi形状记忆合金侧热影响区组织晶粒粗大、硬度降低、 塑性提高。严格控制钎焊工艺参数可以获得具有较高抗拉强度、形状记忆效应和超弹性的TiNi形状记忆合金与不 锈钢钎焊接头。 相似文献
16.
CuZnAl合金的形状记忆效应、力学性能及阻尼性能的好坏是决定其工业实用性的关键指标。采用倒扭摆(JN-1型真空扭摆仪)方法,测试了固溶处理后合金的振动应变振幅爿与振动时间t的关系曲线(自由衰减曲线),并对Zr对CuZnAl合金低频阻尼性能的影响进行了研究,探讨了CuZnAl合金马氏体产生高阻尼特性的微观机制。结果表明,1.2、2.3、1.7三种合金具有最佳阻尼性能的固溶温度分别为800℃、900℃和800℃;相同围溶处理温度8000C下,不含Zr的1.7合全的阻尼性能最佳。含Zr少的1.2合金的阻尼性能好于含Zr多的2—3合金的阻尼性能。 相似文献
17.
18.
19.
In this study, the models of four materials including three sorts of pseudoelastic TiNi alloys and a stainless steel (as a contradistinction) enduring a particle's normal loads were individually simulated based on bilinear strain hardening law by means of finite element method. Owing to the pseudoelasticity, TiNi alloys proved to have high elastic strain limit and low pseudo-Yong's modulus, with which the special mechanical response was created under normal loads. The results shown that pseudoelastic TiNi alloys occurred plastic deformation more difficult than the stainless steel, and the critical load of plastic deformation increased with the increasing elastic strain limit and the decreasing pseudo-Young's modulus. Plastic regions of three TiNi alloys with the elastic strain limit 0.02, 0.04 and 0.06 were 0.60, 0.32, 0.047 times of that of the stainless steel, respectively. When the pseudoelastic TiNi alloys endured a particle's normal loads, the phenomena of decreasing contact stress, von Mises stress and increasing the elastic strain were also observed in this FEM study. In terms of above results, the wear mechanism of pseudoelastic TiNi alloys was discussed finally. 相似文献