What are different components of an engine pylon?
Your question is very broad.  Are you looking for something specific? There isn't really a single configuration where one can simply list standard function of each component, but  I can give broad overview.
Firstly, pylon is also a conduit for multiple systems between aircraft and engine and thus contains secondary structure for mounting them. It looks much like aircraft wing with frames and ribs to support distributed loads. Secondary structure is easily made from aluminum and includes brackets, cleats, supports, stand-offs, and attachment hardware like clamps, nuts, bolts. Also pylon skins/fairings can (depending on design) be minor part of load distribution. But I presume you mean primary structure components that are most directly associated with mounting  the engine.
The functions are to attach/support engine (including withstanding emergency/crash/FBO loads), transmit thrust to airframe, and accommodate engine thermal expansion. Most generically, this is achieved by structural members forming a torque box or space frame. But realization and component names vary a lot. The are two fundamental families depending on attachment: 1) fuselage (i.e.) side-mounted,  and 2) wing (i.e. vertically)-mounted. We won't go into exotics like above-wing &amp; wing-root mounting. Furthermore, there are few styles of wing-mounting (with different components) that fundamentally are driven by relative location of engine to the wing and relative size of engine to aircraft. There are also different mounting philosophies like soft-mounted (with elastomeric vibration isolators) or hard-mounted (without such).
Bear in mind that aircraft structures are designed to distribute load across multiple members and provide redundant load paths, so as to intentionally avoid single point of failure. Having said that,  4 key  elements can be identified:

a forward mounting beam/strut, which is perpendicular to engine axis and usually terminates in a yoke/frame that wraps around engine fan case. It primarily supports engine weight, but also crash loads &amp; lateral FBO loads, including subsequent windmilling.
a thrust strut/link/mount, which is most aligned with engine thrust line, but inevitably runs diagonally to connect engine to pylon structure. It carries most of the thrust load into airframe, but would also carry longitudinal crash loads.
An aft/rear mounting beam/strut, which is also perpendicular to engine axis. Depending on engine size &amp; proportion, in can vary from a frame to yoke to very thin struts. Aft mount's (primary but not only) function is to provide 2nd support point to secure the engine and allow expansion.
Space frame further into the body that disperses the loads and provides rigidity out of principal plane created by elements 1-3.


In a fuse-mounted configuration the principal plane is horizontal and functions are more decoupled. In wing-mounted configurations the principal plane is vertical and some functions &amp; load distributions are more coupled.  Other designs like B-747, where engine hangs far below wing attachment points, rely on a space fame of axial members to suspend the engine in a 3D truss (as can be seen in previous post with link to FAA accident investigation). The functions mentioned before are even more coupled &amp; shared between all members. The names are really irrelevant as Boeing chooses to refer to them as upper/ lower links and side braces.

In terms of actual parts, this is realized by main fittings, sleeves, bushings, alignment pins, load-bearing pins/bolts, etc.
Materials: Actually aluminum is widely used in mounts, with steel as required, and titanium when $/kg weight trade studies justify it. Titanium is expensive &amp; horrendously difficult to machine and is used sparingly, albeit more so on recent designs that push margins. Of course, as everything in such highly complex products, it depends on specifics and sizing of a given design. Temperature must be considered, but is typically not a driving factor, especially for fuselage- mounted  engines,  and areas adjacent to cold sections of the engine. Actually it works out quite well - the heaviest and most loaded section of engine (like fan)is in front, which is cold. The loads are best supported &amp; reacted by a big, intricate mount with large x-section area &amp; moment of inertia (like yoke). Manufacturing it from titanium would be cost prohibitive and it is best made from aluminum. The aft hot section of the engine is supported by simpler, smaller struts that could be made from titanium. For wing-mounted though, the whole pylon area is subject to heat soaking, but weight is more evenly distributed between forward and aft mounts, so having smaller, simpler titanium fittings is practical.