请选择 进入手机版 | 继续访问电脑版
设为首页收藏本站

航空发动机&燃气轮机之家

 找回密码
 立即注册

QQ登录

只需一步,快速开始

扫一扫,访问微社区

搜索
热搜: 活动 交友 discuz

更好的航空发动机 靠高温钛合金行吗?

2017-7-29 09:08| 发布者: admin| 查看: 799| 评论: 234

摘要: 航空发动机材料航空发动机是飞机的心脏、决定飞机的性能、寿命和可靠性。对于发动机而言,一个重要的性能指标是推重比,也就是发动机产生的推力与其质量之比。要提高推重比,给发动机减重是一个重要途径。改变航空发 ...

航空发动机材料



航空发动机是飞机的心脏、决定飞机的性能、寿命和可靠性。对于发动机而言,一个重要的性能指标是推重比,也就是发动机产生的推力与其质量之比。要提高推重比,给发动机减重是一个重要途径。


改变

航空发动机早期采用铝合金、镁合金、高强度钢和不锈钢等制造;而如今为增加发动机推力、提高飞机飞行速度的需要,钛合金、高温合金和复合材料相继得到应用。

Change

钛合金VS镍基高温合金


撇开复合材料,我们今天就钛合金与高温合金的代表——镍基合金做一个比较。


钛的密度比钢轻约40%,而强度与之相当,耐热性、耐蚀性、 弹性、抗弹性和成形加工性均非常优秀。因此,钛合金在航空发动机的应用越来越多。

镍基高温合金指的是以镍为基体在650~1000℃范围内具有较高的强度和良好的抗氧化、抗燃气腐蚀能力的高温合金。镍基高温合金比钛合金要重一倍。

看到这里,你是不是觉得钛合金完全可以把比它重一倍的镍基高温合金挤出发动机,独霸发动机?

抱歉,并没有!

就目前而言,航空发动机的前端——风扇和低压压气机,工作温度较低,一般在350度以下,其叶片、盘件、机匣采用的是Ti-Al合金。而在发动机的高温段部分高压压气机,工作温度一般在500-600度,用的却仍然是镍基高温合金

钛合金的高温性能并没有看起来那么光鲜。钛的熔点1668度,但工作温度高于400度就可以成为高温钛合金,而600度竟然被称为钛合金的“热障”温度,成功闯关的寥寥无几。从20世纪70年代开始,至今四十余年没有工作温度超过600度的钛合金正式服役。

是什么限制了钛合金在更高温度下的使用?


氧化层


高温脱落,化学性质不稳定

随着温度升高而快速下降的表面抗氧化性是一个重要原因。

我们熟知的不锈钢,靠的是其表面形成一层氧化膜,阻止进一步氧化。而钛同样会与氧结合生成一层与基体结合紧密的氧化膜。这层氧化膜,就是钛合金抗氧化性的关键。


氧化薄膜在500度以下非常稳定,但随着温度的升高,氧在钛中的溶解度提高,促使钛的二氧化物反应生成低价氧化物,表面氧化层密度提高而比容降低,氧化物由此会脱落,氧化膜丧失保护作用。


钛火


高温易燃

即使这些年偶有报道某些钛合金的高温性能优越,具备在更高的温度服役的可能。但高温下应用钛合金,还横亘着一座大山,那就是“钛火“,即钛合金发生着火燃烧事件。


钛火故障危害很大,自航空发动机应用钛合金以来,就不断发生钛火事故,仅仅2-20s就可能完全烧尽钛合金零部件和发动机,并且找不到有效灭火措施。

 

钛在空气中的熔点是1627度,而高温钛合金的工作温度尚不超过600度。两者之间相差很大,一般情况下是不会发生燃烧事件。



但是高压压气机叶片故障,导致断片、碎片造成剧烈摩擦,产生大量热量,或者压气机失速引起发动机气流反向流动,从燃烧室后段返回的气流温度都一般高过钛的燃点,都会造成钛火事件。


且不说在600度以上高温,目前研发的钛合金的总体力学性能对于镍基高温合金并无多大优势。如果解决不了钛火问题,高温钛合金在航发上难有更大作为阻燃涂层是避免钛火的一种方式。它是采用先进的喷涂工艺在钛合金零部件表面涂覆一层难以燃烧的材料,延缓和阻止燃烧的作用。不过,阻燃涂层存在脱落的危险,而且它也不能提高钛合金的使用温度。


鲜花

握手

雷人

路过

鸡蛋
发表评论

最新评论

引用 游客 2018-5-27 02:42
ordering viagra in uk
<a href="http://viagranbdnr.com/#">viagra without a doctor prescription usa</a>
where to buy viagra online uk
[url=http://viagranbdnr.com/#]viagra without doctor prescription[/url]
precio sildenafil 50 mg
<a href="http://canadamdonlineget.com/#">legitimate canadian mail order pharmacies</a>
what is the best website to buy viagra online
[url=http://canadamdonlineget.com/#]canadian pharmacies shipping to usa[/url]
viagra cheap discount ...
引用 游客 2018-5-25 19:30
cheap viagra kamagra from the u.k
<a href="http://viagranbdnr.com/#">viagra without a doctor prescription</a>
price of viagra pills
[url=http://viagranbdnr.com/#]viagra without a doctor prescription[/url]
viagra sale in india
<a href="http://canadamdonlineget.com/#">canadian pharmacies online prescriptions</a>
can u get viagra
[url=http://canadamdonlineget.com/#]canadian pharmacies online[/url]
sildenafil 100 mg viagra
引用 游客 2018-5-25 18:39
sildenafil generico mexico
<a href="http://canadamdonlineget.com/#">canada pharmacies</a>
pfizer brand viagra online
[url=http://canadamdonlineget.com/#]top rated online canadian pharmacies[/url]
buy viagra at boots
<a href="http://viagradcvy.com/#">viagra without doctor prescription</a>
generic viagra accept paypal
[url=http://viagradcvy.com/#]generic viagra without a doctor prescription[/url]
viagra generico em curitiba
引用 游客 2018-5-25 07:57
cheap viagra canada pharmacy
<a href="http://canadamdonlineget.com/#">best canadian mail order pharmacies</a>
what to tell the dr to get viagra
[url=http://canadamdonlineget.com/#]canadian online pharmacies[/url]
legality of buying viagra online
<a href="http://viagradcvy.com/#">generic viagra without a doctor prescription</a>
where to buy viagra for the brain
[url=http://viagradcvy.com/#]viagra without a prior doctor prescription[/url]
buy individual viag ...
引用 游客 2018-5-23 08:06
can i safely take 200mg of viagra
<a href="http://viagramakay.com/#">generic viagra without a doctor prescription</a>
how much does viagra cost at target
[url=http://viagramakay.com/#]generic viagra without a doctor prescription[/url]
ways to get an erection without viagra
<a href="http://canadamypharmacykee.com/#">online canadian pharmacies</a>
sildenafil effervescent tablets use
[url=http://canadamypharmacykee.com/#]canadian pharmacies online prescriptions ...
引用 游客 2018-5-23 06:58
preco do viagra generico
<a href="http://viagramakay.com/#">viagra without a doctors prescription</a>
viagra price canada
[url=http://viagramakay.com/#]viagra without doctor[/url]
can i buy viagra from shoppers drug mart
<a href="http://canadamypharmacykee.com/#">top rated online canadian pharmacies</a>
generic viagra soft tabs 50 mg
[url=http://canadamypharmacykee.com/#]list of reputable canadian pharmacies[/url]
viagra online for free
引用 游客 2018-5-22 18:55
buy viagra from brazil
<a href="http://viagramakay.com/#">viagra without a prior doctor prescription</a>
wie wirkt viagra 100mg
[url=http://viagramakay.com/#]viagra without a doctors prescription[/url]
happens if girl takes viagra pill
<a href="http://canadamypharmacykee.com/#">legitimate canadian mail order pharmacies</a>
cheap viagra generic canada
[url=http://canadamypharmacykee.com/#]canadian pharmacies online prescriptions[/url]
nome de genericos do v ...
引用 游客 2018-5-22 12:51
how to get rid of viagra ads
<a href="http://viagramakay.com/#">viagra without a doctor prescription</a>
comprar viagra precisa de receita medica
[url=http://viagramakay.com/#]viagra without a prior doctor prescription[/url]
buy viagra mumbai
<a href="http://canadamypharmacykee.com/#">canadian pharmacies online</a>
can i get in trouble for ordering viagra online
[url=http://canadamypharmacykee.com/#]best canadian mail order pharmacies[/url]
viagra online u ...
引用 游客 2018-5-22 12:03
buy generic viagra bangkok
<a href="http://viagramakay.com/#">viagra without a prior doctor prescription</a>
generic sildenafil citrate by teva pharms
[url=http://viagramakay.com/#]generic viagra without a doctor prescription[/url]
what is the use of viagra pill
<a href="http://canadamypharmacykee.com/#">canadian pharmacies that ship to the us</a>
viagra generic in australia
[url=http://canadamypharmacykee.com/#]aarp recommended canadian pharmacies[/url]
r ...
引用 游客 2018-5-22 00:08
viagra 100 mg bula
<a href="http://viagramakay.com/#">viagra without doctor</a>
viagra price 2012
[url=http://viagramakay.com/#]viagra without doctor[/url]
cheap sildenafil tablets
<a href="http://canadamypharmacykee.com/#">canadian pharmacies online prescriptions</a>
what is the use of viagra tablet
[url=http://canadamypharmacykee.com/#]legitimate canadian mail order pharmacies[/url]
viagra magnum 50 mg
引用 游客 2018-5-21 22:49
how to buy real viagra online
<a href="http://viagramakay.com/#">generic viagra without a doctor prescription</a>
comment utiliser viagra 100mg
[url=http://viagramakay.com/#]viagra without doctor[/url]
dejavu generico viagra
<a href="http://canadamypharmacykee.com/#">best canadian mail order pharmacies</a>
buy viagra generics nl
[url=http://canadamypharmacykee.com/#]best canadian mail order pharmacies[/url]
sildenafil citrate buy cheap
引用 游客 2018-5-19 17:05
como se llama el generico de viagra
<a href="http://viagratvbsugg.com/#">viagra without a doctors prescription</a>
muse viagra together
[url=http://viagratvbsugg.com/#]viagra without prescription[/url]
what is cheaper viagra cialis levitra
<a href="http://canadianmjdpharmacieskl.com/#">aarp recommended canadian pharmacies</a>
how long does it take for a viagra pill to work
[url=http://canadianmjdpharmacieskl.com/#]legitimate canadian mail order pharmacies[/u ...
引用 游客 2018-5-19 17:05
viagra generico spagna
<a href="http://canadianmjdpharmacieskl.com/#">canadian pharmacies online</a>
old can you get viagra
[url=http://canadianmjdpharmacieskl.com/#]canada pharmacies[/url]
esiste il farmaco generico del viagra
<a href="http://viagrabndoctorjaa.com/#">viagra without a prior doctor prescription</a>
viagra online shop india
[url=http://viagrabndoctorjaa.com/#]viagra without a doctor prescription[/url]
do you need a prescription to buy viagra ...
引用 游客 2018-5-19 08:23
swiss viagra pill splitter
<a href="http://canadianmjdpharmacieskl.com/#">viagra without doctor</a>
real viagra online buy
[url=http://canadianmjdpharmacieskl.com/#]viagra without prescription[/url]
tescos viagra online
<a href="http://viagrabndoctorjaa.com/#">legitimate canadian mail order pharmacies</a>
rate generic viagra
[url=http://viagrabndoctorjaa.com/#]canadian pharmacies online prescriptions[/url]
cheap viagra from india
引用 游客 2018-5-19 07:14
where can i buy viagra for cheap
<a href="http://viagratvbsugg.com/#">viagra without doctor</a>
hard sell evolution viagra salesman quotes
[url=http://viagratvbsugg.com/#]viagra without doctor prescription[/url]
cheapest super viagra
<a href="http://canadianmjdpharmacieskl.com/#">best canadian mail order pharmacies</a>
50mg viagra doesnt work
[url=http://canadianmjdpharmacieskl.com/#]canadian online pharmacies[/url]
get real viagra online ...
引用 游客 2018-5-18 18:23
viagra sildenafil citrate 100mg
<a href="http://canadianmjdpharmacieskl.com/#">canadian pharmacies shipping to usa</a>
order viagra professional
[url=http://canadianmjdpharmacieskl.com/#]list of reputable canadian pharmacies[/url]
viagra where to buy in uk
<a href="http://viagrabndoctorjaa.com/#">viagra without a prior doctor prescription</a>
where can i buy viagra london
[url=http://viagrabndoctorjaa.com/#]viagra without a prior doctor prescription[/url]
...
引用 游客 2018-5-18 18:20
cialis levitra viagra prices
<a href="http://viagratvbsugg.com/#">generic viagra without a doctor prescription</a>
buy viagra online no rx
[url=http://viagratvbsugg.com/#]viagra without a doctors prescription[/url]
viagra generic in 2012
<a href="http://canadianmjdpharmacieskl.com/#">canada pharmacies</a>
viagra anxiety disorder
[url=http://canadianmjdpharmacieskl.com/#]canadian pharmacies shipping to usa[/url]
buy viagra overnight shipping ...
引用 游客 2018-5-18 09:41
online apotheke deutschland viagra
<a href="http://canadianmjdpharmacieskl.com/#">viagra without doctor</a>
cialis viagra online canada
[url=http://canadianmjdpharmacieskl.com/#]viagra without prescription[/url]
viagra at tesco online
<a href="http://viagrabndoctorjaa.com/#">list of reputable canadian pharmacies</a>
viagra cheap india
[url=http://viagrabndoctorjaa.com/#]canadian pharmacies shipping to usa[/url]
sildenafil online paypal
引用 游客 2018-5-18 08:36
viagra generico em curitiba
<a href="http://viagratvbsugg.com/#">viagra without a doctors prescription</a>
how can i order viagra
[url=http://viagratvbsugg.com/#]viagra without a doctor prescription[/url]
where can i buy cialis or viagra on line
<a href="http://canadianmjdpharmacieskl.com/#">canada pharmacies online prescriptions</a>
getting emails myself viagra
[url=http://canadianmjdpharmacieskl.com/#]list of reputable canadian pharmacies[/url]
can buy v ...
引用 游客 2018-5-17 11:47
happens you take cialis viagra together
<a href="http://viagratvbsugg.com/#">viagra without a doctor prescription</a>
viagra generico precio
[url=http://viagratvbsugg.com/#]viagra without a prior doctor prescription[/url]
cheap viagra online canada
<a href="http://canadianmjdpharmacieskl.com/#">legitimate canadian mail order pharmacies</a>
where can you buy viagra over the counter in canada
[url=http://canadianmjdpharmacieskl.com/#]legitimate canadian mail o ...

查看全部评论(234)

QQ|Archiver|手机版|小黑屋|航空发动机&燃气轮机之家 ( 沪ICP备16010109号  

GMT+8, 2018-5-27 17:37 , Processed in 0.082771 second(s), 19 queries .

Powered by Discuz! X3.2

© 2001-2013 Comsenz Inc.

返回顶部