Source: Alcoa.

As 2015 gets under way, investors are looking for signs that the New Year will continue the six-year-old bull market, and the beginning of earnings season will provide plenty of information about the sustainability of the stock market's long rally. On Monday afternoon, aluminum-maker Alcoa (NYSE:AA) got things going with its fourth-quarter financial report, and even though the stock has climbed an impressive 60% since this time last year, Alcoa's latest results were full of optimism not just for the company but for the materials sector as a whole. Let's take a closer look at how Alcoa did in the fourth quarter and what's ahead for Alcoa in 2015.

Alcoa: full speed ahead
In the fourth quarter, Alcoa continued a string of favorable results it has produced in recent quarters. On the whole, the aluminum giant had net income of $159 million, or $0.11 per share. But again, Alcoa's results included substantial charges related to its internal restructuring efforts, and when you add back in the $273 million in special charges, Alcoa earned an adjusted $0.33 per share. That was quite a bit more than the $0.25 per share that investors had expected from the aluminum company. Total sales were $6.38 billion for the quarter, up more than 14% from the year-ago quarter and almost doubling the growth pace that investors had looked for.

Alcoa's major business segments also performed well, albeit with the need for some additional explanation. The Engineered Products and Solutions business, which holds most of Alcoa's most essential value-added manufactured aluminum products, saw after-tax operating income inch downward by 2% from the year-ago quarter. Yet after backing out costs related to the Firth Rixson acquisition, Alcoa claimed a 19th straight quarter of growth as well as stronger margins for the key segment. Meanwhile, Global Rolled Products got a big boost, with operating income more than tripling from year-ago levels. Alcoa's Alumina and Primary Metals segments had similarly impressive performance, with Alumina operating income climbing by more than 150% and Primary Metals reversing a year-ago loss with a huge $267 million profit.

Source: Alcoa.

Alcoa CEO Klaus Kleinfeld touted the achievement, noting that the quarter's results "capped a pivotal year as we significantly accelerated Alcoa's transformation." In discussing the results for the full year, Kleinfeld pointed out that Alcoa's operating results in 2014 were the best in six years and as he sees it, the company will "enter 2015 on solid footing, poised to continue transforming and growing."

What Alcoa's transformation means for shareholders
Alcoa has made big strides forward in 2014 in all of its businesses. The completion of the Firth Rixson acquisition will bring a massive increase in overall revenue, and the buyout of titanium aerospace-component maker TITAL should further diversify Alcoa beyond aluminum. Meanwhile, with its new Micromill manufacturing technology, Alcoa will provide the materials that automakers can use for a wide array of parts and components, and it has sold off lower-margin production facilities to boost Alcoa's exposure to higher-growth areas.

Source: Alcoa.

At the same time, the upstream commodity business has been a pleasant surprise to Alcoa investors. Given the relative weakness in aluminum prices, Alcoa has shown a remarkable ability to boost profitability in the segment, but its sale of higher-cost mining and refining operations has paid off with much better operating income. The company's efforts to cut back on smelting capacity during a time of low demand has helped Alcoa make the most of a tough situation.

What will 2015 bring for Alcoa?
Alcoa remains optimistic about how 2015 will go. It sees revenue growth in the key global aerospace arena of about 9% to 10%, as aircraft and jet-engine production volume remains strong. Automotive production growth will remain slower at 2% to 4%, and the pace of commercial transportation-related growth will slow markedly to around 3% to 7% in North America and -1% to 3% worldwide. Overall, Alcoa once again sees global demand for aluminum climbing at a 7% clip in 2015, equaling its pace in last year. The building and construction market should grow at about a 5% to 7% pace but continue to show the disparities in the world economy, with North American sales climbing strongly but Europe staying sluggish.

Alcoa's report initially got a positive reaction for investors, with the share price climbing around 1.5% within the first 45 minutes after the report in after-hours trading. With the aluminum giant still on track to capitalize on growth opportunities, Alcoa looks stronger than ever and well-poised to capture further gains in 2015.